Diet energy and feed intake in chickens

Impact of extended lairage periods on physio-metabolic status and meat quality in commercial broilers

1. This study investigated the impact of different lairage duration on physiology, metabolism and meat quality in commercial broilers.2. A total of sixty, one-d-old Vencobb broilers were reared until 42 d of age and subjected to five lairage treatments (T0-T5), with the control with no lairage and then each timepoint increasing by 2 h.3. Head, eye and feet temperature increased progressively (P˂0.05), from 21 to 42 d. During lairage, temperature for the head, eye and feet were significantly higher in birds held until T3-T4 (P˂0.05), than at T0-T2 and T5 treatments.4. Serum total protein, creatinine, lipase and TBARS showed no variation due to lairage (p > 0.05). Glucose levels were highest at T4 (p < 0.05) than at T1-T3 or T5 and serum albumin increased only at T4 as compared to T5 (p < 0.05). Higher levels for blood triglycerides were recorded for T0, T1 and T5 (p < 0.05), than at T2-T4 and total blood antioxidants were significantly higher at T1 (p < 0.05), than at T0 and T2-T5 treatments, respectively.5. There was no significant difference for meat pH, ERV and WHC (p > 0.05), while, higher tyrosine levels (p < 0.05) were noted for birds in T5 than for the rest of the lairage treatments (T0-T4). On the same trend, TBA concentration was highest for birds in T5, as compared to T4 (p < 0.05).6. In conclusion, lairage over eight hours for commercial broilers is not recommended, as there are drastic changes in physiology, metabolism and deterioration of meat, reducing meat quality.

Metabolizable and net energy evaluation of corn, soybean meal, and wheat bran in growing male pheasants

The apparent metabolizable energy(AME), AME corrected to zero-nitrogen retention(AMEn) and net energy (NE) values of corn, soybean meal and wheat bran were determined in growing male pheasants with reference diet substitution method. Reference diet was formulated according to standard Pheasants requirement, and test diets contained 40 % of corn, 20 % of soybean meal and 30 % of the wheat bran samples of thereference diet. Ninety male pheasants at the age of 12 wk with similar body weights were randomly divided into four groups. The heat production and energy metabolism of birds were measured in open-circuit respiratory chambers with 6 replicates (4 birds per replicate) per diet in a randomized design. Birds were fed experimental diets for 6 D in the chamber as adaptation. During the following 3 D, feed intake, metabolizable energy value, nitrogen balance, energy balance, O2 consumption, CO2 production, and energy efficiency were determined. Pheasants were allowed free access to feed under controlled environmental conditions. Feces were collected using respiratory calorimetry. The AME values of corn, soybean meal and wheat bran were 14.62 MJ/kg, 10.62 MJ/kg and 7.57 MJ/kg DM, respectively. The corresponding AMEn values were 14.71 MJ/kg, 10.64 MJ/kg and 7.25 MJ/kg DM, respectively. The NE values were 11.20 MJ/kg, 7.02 MJ/kg, and 6.19 MJ/kg DM, respectively. The NE:AME ratios of corn, soybean meal and wheat bran were 77.61 %, 65.68 % and 85.17 %, respectively. The NE:AMEn ratios of corn, soybean meal and wheat bran were77.22 % and 66.89 % and 84.76 %, respectively. The AME, AMEn and NE values of corn were higher than the other two samples.

Enhancing nutrient intake, egg production, and egg quality by fermented Leucaena leucocephala leaf meal in a diet of laying quail

Background and Aim

The inclusion of Leucaena leucocephala leaf meal (LLM) in poultry feed is often limited due to its high crude fiber and mimosine content. This study investigates the potential of fermented LLM (FLM) to enhance nutrient intake, egg production, and egg quality in laying quails by reducing anti-nutritional factors through fermentation.

Materials and Methods

Two hundred 42-day-old laying quails were assigned to five dietary treatments: T0 (control) = 100% basal diet (BD), T1 = 98% BD + 2% FLM, T2 = 96% BD + 4% FLM, T3 = 94% BD + 6% FLM, and T4 = 92% BD + 8% FLM. Parameters including nutrient intake (energy, protein, fat, calcium, phosphorus), feed conversion ratio (FCR), egg production, egg weight, eggshell thickness, Haugh unit, and yolk color were measured over a 28-day trial. Data were analyzed using a one-way analysis of variance, followed by Duncan's test for significant differences (p ≤ 0.05).

Results

FLM supplementation significantly improved energy, protein, fat, calcium, and phosphorus intake while reducing FCR. At 4% FLM inclusion, significant enhancements in egg production, eggshell thickness, Haugh unit, and yolk color were observed. Conversely, fiber intake and overall feed intake remained unaffected across treatments. The highest egg production (56.43%) and best yolk color (8,95) were observed in the 8% FLM group.

Conclusion

Incorporating FLM into the diets of laying quails effectively enhances nutrient utilization and improves egg production and quality without increasing feed intake. The optimal inclusion level for maximizing benefits appears to be 4-8% FLM.

Increasing digesta viscosity altered nutrient transporter gene expression and decreased nutrient utilisation in Eimeria-challenged birds

1. Two experiments were conducted, the first was to investigate the effect of increasing digesta viscosity by dietary carboxymethyl cellulose (CMC) on the growth performance and intestinal morphology and characteristics of healthy birds. The second experiment evaluated the impact of increased digesta viscosity in birds during an Eimeria spp. challenge.2. In experiment 1, a corn-soybean meal-based basal diet was supplemented with 0, 10 or 20 g/kg CMC at the expense of cornstarch and offered to seven birds in each of eight replicate cages per diet from d 8 to 22 post hatching.3. Increasing digesta viscosity due to dietary CMC linearly reduced (p < 0.05) body weight (BW) gain and the apparent ileal digestibility of nutrients. The relative lengths of the duodenum, jejunum and ileum linearly increased (p < 0.01) with dietary CMC inclusion.4. In experiment 2, on d 14, 256 broiler chickens were randomly assigned to eight replicate cages in a 2 × 2 factorial arrangement of treatments with two CMC concentrations (0 or 10 g CMC/kg of diet), with or without an Eimeria challenge. On d 15, birds in the challenge groups were orally gavaged with a 1 ml solution containing 25,000, 25,000 or 125,000 oocysts of E. maxima, E. tenella and E. acervulina; or 1% PBS, respectively.5. Increasing digesta viscosity in Eimeria-challenged birds decreased the total tract digestibility of dry matter and gross energy (p < 0.05). The ileal gene expression of glucose transporters was upregulated (p < 0.05) in challenged birds that received the CMC-supplemented diet.6. In summary, increased digesta viscosity induced changes in the expression of nutrient transporter genes and decreased nutrient utilisation in Eimeria-challenged birds.

Interactive effects of dietary energy levels with amino acid density on growth performance and optimal digestible Lys to energy ratio of male broiler chickens

A total of 2,400 day-old off-sex male Ross 308 chicks were used in a 4 × 3 factorial array (8 replicates with 25 birds per replicate) to determine the interactive effects of dietary metabolizable energy (ME) and amino acid (AA) densities on productive traits of broiler chickens reared to 42 d of age. The experimental factors were 4 ME levels (control, -50, -100, -150 kcal) and 3 digestible AA levels (control, +3.0 and +6.0%). Diets were fed for starter (0-10 d), grower (11-24 d), finisher (25-35 d), and withdrawal (36-42 d) phases, with consistent reduction of ME and increase in AA density for each phase. Overall, ME reduction did not compromise final body weight (BW; d 42). However, when ME was reduced by 50 kcal, only the diets with +6% AA density improved BW, resulting in an interaction between ME and AA levels (P < 0.05). Reducing ME and increasing AA densities independently increased total feed intake (P < 0.01). An interaction between ME and AA density on feed conversion ratio (FCR) was observed where increasing AA density at both +3.0 and +6.0% levels at control ME reduced FCR, but with reduced ME diets, FCR was reduced only at +6% AA density (P < 0.01). Quadratic broken line models estimated a digestible Lys to ME ratio (mg Lys/1,000 kcal ME) of 474 and 407 in starter and grower diets, respectively, to optimize both BW and FCR. However, in finisher phase a ratio of 363 could only be predicted for optimal FCR and in withdrawal a ratio of 349 to optimize BW. In summary, these results indicate that the interaction between ME and AA densities affects the productive traits of broiler chickens. Increasing AA density at control ME density improves FCR, while reduced ME diets require higher AA density to improve FCR. Quadratic broken line models suggest specific digestible Lys to ME ratios for optimizing BW and FCR across different phases of the production cycle.

Effects of Dietary Protein Levels, Net Energy Levels, and Essential Amino Acid-to-True Protein Ratios on Broiler Performance

Supplementing essential amino acids (EAAs) without considering non-EAA (NEAA) and energy contents in reduced-crude protein (CP) diets may alter EAA-to-true protein (E:T) and energy-to-protein ratios, potentially compromising growth. This study aimed to evaluate the effects of CP, E:T, and net energy (NE) on broiler performance. The treatments were as follows: T1-reduced CP (16%, RP), low NE (9.9 MJ/kg, LNE), low E:T (0.56, LE:T); T2-RP, LNE, high E:T (0.60, HE:T), with imbalanced EAA (excess Met and deficient Thr); T3-RP, high NE (10.4 MJ/kg, HNE), LE:T; T4-RP, HNE, HE:T; T5-normal CP (18%, NP), LNE, LE:T; T6-NP, LNE, HE:T; T7-NP, HNE, LE:T; and T8-NP, HNE, HE:T. The study employed as-hatched Cobb 500 broilers in two experiments. Exp.1 studied the broiler performance from d19 to 35, with eight replicates per treatment and 16 birds per replicate (n = 1024). Birds were randomly assigned to different treatments, and at the end of their lives, all were dissected to determine their sex and account for any gender-related effects. Exp.2 measured NE values in respiration chambers from d25 to 28, with six replicates per treatment, and two birds (a male and a female) per replicate (n = 96). The bird gender was determined through high-resolution melting curve analysis of feather DNA. The measured NE values were used to calculate NE intake (NEi) in Exp.1. The results showed that T4 improved (p < 0.001) weight gain (WG), feed conversion ratio (FCR), and NEi relative to T1, T2, and T3, and protein efficiency (WG/CP intake) relative to all treatments. The live performance (feed intake, WG, FCR) and NEi of birds fed T4 reached a level equal to those of birds fed NP diets (T5 to T8). These results suggest that a dietary E:T ratio of 0.60 is necessary to maximize nutrient utilization and to restore growth rate in broilers fed RP diets.

Dietary fat and high energy density diet: Influence on intestinal health, oxidative stress and performance of weaned piglets

The utilization of dietary components to support gut function and the health of young animals is an important factor for improved performance. The influence of high dietary fat levels in a low or high energy density diet on the performance of weaned piglets in relation to intestinal absorptive function, amino acid utilization, oxidative stress, and microbial metabolites was assessed in this study. The study examined the effect of two different diets containing either a low energy density/high-fat level or a high energy density/high-fat level. A total of 16 healthy weaners (9.60 ± 0.13 kg) were allocated to one of the two dietary treatments. There were eight weaners per treatment. Results showed that feed intake and body weight gain of weaners were increased by the diet of high energy density/high-fat level (p < 0.05), but the feed efficiency showed an increased tendency of significance (p = 0.05). In the duodenum, the villus height (VH) and VH/crypt depth (CD) ratio (VH:CD) were increased by dietary high energy density/high fat. In the jejunum and ileum, the CD was increased by low energy density/high-fat diet, while the goblet cell count and VH:CD were increased by dietary high energy density/high-fat level. Methionine, lysine and phenylalanine concentrations were increased by high energy density/high-fat diet while low energy density/high-fat diet showed an increased tendency to increase citrulline and ornithine concentrations in the piglet. Oxidative stress marker, lactase enzyme activity and serum calcium concentration were increased by a high energy density/high-fat diet. Increased dietary fat in all diets induced diarrhoea in the weaners (p < 0.01). It was concluded that a dietary high energy density/high-fat diet seems to positively modulate gut absorptive function, serum amino acid (methionine and lysine), calcium levels and increased oxidative stress markers in the weaned piglets.

Supplementing low protein diets with methionine or threonine during mixed Eimeria challenge

We investigated the effects of supplementing low protein diets with methionine (Met) or threonine (Thr) during a mixed Eimeria (consisting of E. acervulina, E. maxima and E. tenella) challenge in broilers. All birds were fed the same starter diet (d1-9) and finisher diet (d28-35) which met Cobb 500 nutrient specifications. Birds were allocated to 1 of 4 dietary treatments from d9 to 28: a standard protein diet (19% CP); a low protein diet (16% CP); or the low protein diet supplemented with Met or Thr at 50% above recommendations. On d14, half of the birds were challenged, and half of the birds were unchallenged. From d14 to 28, feed intake was recorded daily and BW every 3 or 4 d. Oocyst excretion was measured daily from d18 to 27. On d21 and 28, 3 birds per pen were euthanized to assess nutrient digestibility, cytokine expression and intestinal histology. During the acute stage of the challenge, challenged birds reduced ADFI and ADG (P < 0.05). In the pre-patent and recovery stages, birds given the 16% CP diets increased ADFI (P < 0.05), meanwhile there were no differences in ADG in these stages (P > 0.05). Nutrient digestibility was reduced in challenged birds in the acute stage (P < 0.05) but tended to be greater than in unchallenged birds during the recovery stage. There was no significant effect of diet on oocyst excretion or intestinal histology (P > 0.05). Interactions were observed between diet and challenge on IL-10 and IL-21 expression in the cecal tonsils during the acute stage of the challenge (P < 0.05), due to reduced IL-10 expression in challenged Thr birds and greater IL-21 expression in challenged Met birds. Supplementation with Thr or Met had limited effects on the outcomes of a mixed Eimeria challenge but provides benefits to the host by enhancing their immune response.

Taste Preferences in Broilers: Effect of Age, Delivery Matrix, and Number of Chickens per Pen on Selection and Consumption Behaviour

Due to substantial differences between studies, the understanding of avian taste perception remains incomplete. Also, studies on chicken taste preferences have mainly focused on measuring consumption differences, neglecting consumption behaviour patterns. This study investigated how age, the compound delivery matrix, and the number of birds per pen affect broiler chicken preferences and consumption behaviour, and established their preference values for four taste compounds. Ninety-six one-day-old male broiler chickens (Ross 308) were divided into two age groups (initial: days 7-23; final: days 26-42), with two compound delivery matrices (water or ground wheat) and two numbers of birds (one or two chickens per pen), following a 2 × 2 × 2 factorial design. Four taste compounds (sucrose, monosodium glutamate (MSG), L-lysine, and calcium carbonate) were tested at different concentrations. Preferences were assessed at 2, 4, and 8 h post-test, along with recording various behavioural parameters. Initial-stage birds showed higher (p < 0.001) preference values, time of approach (TA), number of bouts (NB), duration of bouts (DB), and number of pecks (NP) than final-stage birds. Birds exposed to a water matrix also exhibited higher (p < 0.001) preference and NB, while those exposed to a ground wheat matrix showed a higher (p < 0.001) NP. Pens with a pair of birds had a higher (p < 0.003) 2 h preference, TA, NB, DB, and NP, than pens with a single chicken. Chickens showed significant preference values for 100 mM sucrose at 2 h (p = 0.025), 150 mM MSG at 4 h (p = 0.026) and 8 h (p = 0.013), and 300 mM MSG at 2 h (p = 0.013). We concluded that all the variables evaluated influence broilers' taste preferences and consumption behaviour during selection tests. Future studies should prioritize including chickens in the initial stage of the production cycle, testing them in pairs or groups, and delivering compounds via a liquid matrix.

Research Note: Effect of increasing fat supplementation in diets on productive performance, egg quality, and fatty liver incidence in laying hens throughout the entire laying cycle

This study aimed to investigate the effect of increasing fat supplementation in diets on productive performance, egg quality, and fatty liver incidence in laying hens during the entire laying cycle. A total of three hundred eighty-four 18-wk-old Hy-Line Brown laying hens were randomly allotted to 1 of 3 dietary treatments with 8 replicates for a 52-wk feeding trial. Each replicate comprised 16 consecutive cages with 1 hen per cage. The experimental diets were prepared by supplementing 0, 1.5, or 3.0% tallow to a basal diet, but all nutrients and energy in 3 diets were formulated to be equalized according to the recommended nutrient and energy concentrations at each phase of laying hens. Results indicated that increasing fat supplementation in diets decreased (linear, P < 0.01) feed conversion ratio (FCR) by increased egg mass (linear, P < 0.05) but decreased feed intake (linear and quadratic, P < 0.05) in laying hens during overall periods. Increasing fat supplementation in diets decreased (linear and quadratic, P < 0.05) egg yolk color during overall periods. Increasing fat supplementation in diets had no effects on liver color and hemorrhagic score measured at 60 wk (phase 3) and 70 wk of age (phase 4) without affecting hepatic fat concentrations during overall periods. However, the relative abdominal fat weight in laying hens was increased (linear and quadratic, P < 0.05) during overall periods by increasing fat supplementation in diets. In conclusion, increasing fat supplementation up to 3.0% in diets improves FCR with no impacts on fatty liver incidence and economics in laying hens throughout the entire laying cycle.

Diet of Broilers with Essential Oil from Citrus sinensis and Xylopia aromatica Fruits

This study aimed to evaluate the effects of essential oils from the fruits of Citrus sinensis and Xylopia aromatica, included in broiler feed, on blood parameters, the biometrics of digestive organs, bone analyses, and the biochemical profiles of the viscera, as well as the histomorphometry of the small intestine. In this study, 180 one-day-old male chicks of the Cobb 500 strain were fed a corn and soybean meal over three treatments and six replications, and the experimental design was completely randomized. The data were subjected to an analysis of variance and a Tukey test at a 5% significance level. The effect of the experimental diets on performance, blood parameters, biometrics of the digestive organs, bone analysis, and biochemical profiles of the viscera, as well as the histomorphometry of the small intestine, were evaluated. The compounds identified in the essential oil of X. aromatica were sylvestrene, α-pinene, and β-pinene, while in C. sinensis they were limonene and myrcene. The essential oils of C. sinensis and X. aromatica had no significant effect on performance at 14 days. The effects of the presence of the essential oils of C. sinensis and X. aromatica on the response were beneficial: there were reductions in liver lipids, cholesterol, and triglycerides, and in the depths of the crypts in the jejunum of chickens. So, the essential oils from the fruits of C. sinensis and X. aromatica can be used in broiler chickens to improve the lipid profiles of birds without affecting their performance.

Optimal dietary energy and protein levels for breeding pigeons in the winter "2 + 3" lactation pattern

The nutritional requirements of breeding pigeons depend on their physiological period, breeding pattern, and environmental conditions. Despite works on reduced litter size in winter production to combat high mortality and the poor welfare of squabs, there are few studies on the related nutritional requirements of these pigeons. A total of 432 pairs of European Mimas pigeons were randomly divided into 9 groups in which 3 crude protein (CP) levels (15, 16.5, and 18%) and 3 metabolizable energy (ME) levels (12.2 MJ/kg, 12.4 MJ/kg, and 12.6 MJ/kg) were tested to determine the optimal energy and protein requirements of breeding pigeons in the winter "2 + 3" breeding pattern. The results showed that ME and CP levels had little effect on the body weight, feed intake, and egg quality of breeding pigeons during the lactation period. An 18% CP diet significantly increased the laying rate and hatchability (P < 0.05), but there was no difference in the laying rate with 18% CP and 16.5% CP during the whole reproductive cycle (P > 0.05). There was a significant interaction between ME and CP levels, and the laying interval of breeding pigeons in group 9 (18% CP; 12.6 MJ/kg) was significantly shortened (P < 0.05). For squabs, the ME level had no effect on growth performance, slaughter performance, or meat quality. The body weight of 21-day-old squabs in the 18% CP group increased by 3.16% compared with that of the 15% CP group, but there was no difference between the 18% CP and 16.5% CP groups. Compared with other experimental groups, group 7 (18% CP; 12.2 MJ/kg) had the fastest growth rate in squabs (P < 0.05), and the corresponding slaughter weight was also the heaviest (P < 0.05). We further found that the height of the squab intestinal epithelium was significantly increased in both the 16.5% CP and 18% CP groups of squabs (P < 0.01), but male breeding pigeons showed a certain degree of oxidative stress with an increase in CP level. In conclusion, the effects of 15 to 18% CP levels and 12.2 to 12.6 MJ/kg ME levels on the reproductive metabolism of breeding pigeons and the growth and development of squabs in the "2 + 3" breeding pattern during winter are small. For economic efficiency, we suggest that the CP level can be reduced to 16.5% while the ME level should not be less than 12.2 MJ/kg in practical production.

Refining the metabolisable energy value of field beans for turkeys

1. This study examined the feeding value of ten UK grown field bean (Vicia faba L. var. minor) cultivar samples from the same harvest year on nitrogen corrected apparent metabolisable energy (AMEn) and nutrient retention coefficients when fed to young female turkeys.2. A balancer feed (BF) was formulated to contain 12.39 MJ/kg ME and 269 g/kg crude protein. Ten nutritionally complete, mash diets were prepared by mixing 200 g/kg of each ground field bean cultivar with 800 g/kg of the BF, totalling eleven diets. Diets were fed to female BUT Premium turkeys from 40 to 50 d of age. Each diet was fed to eight raised floor pens, housing two birds, following randomisation. The AMEn was determined by the total collection technique over the last 4 d of the study. Relationships were examined between AMEn, chemical composition and quality variables of the field bean samples.3. The overall determined AMEn value of the beans ranged from 7.72 MJ/kg DM to 9.87 MJ/kg DM, giving an average AMEn of 8.80 MJ/kg DM (P < 0.05). The soluble non-starch polysaccharide (NSP) content of the beans negatively correlated with their determined AMEn (r = -0.730; P < 0.05). Bean flour lightness-darkness degree (L*) correlated positively with the AMEn (r = -0.643; P < 0.05)4. A positive correlation was observed between the degree of yellowness-blueness of bean flour and condensed tannins content (r = 0.696; P < 0.05). Step-wise regression indicated that soluble NSP + L* of field beans provided explanatory variables suitable for estimating the AMEn value for turkeys (r2 = 0.737; P < 0.05).

Effects of Different Doses of Multienzyme Supplementation on Growth Performance, Duodenal pH and Morphology, and Carcass Traits in Broilers Fed Diets with an Increasing Reduction in Energy

This study evaluated the effects of supplementing different doses of a multienzyme (KZP) consisting of carbohydrases and a protease on growth performance, duodenal pH and morphology, and carcass traits in broilers fed diets with increasing reductions in energy. One thousand two hundred one-day-old broiler chicks were allocated to five dietary treatments with eight replicates of 30 birds each: a positive control diet formulated to meet Arbor Acres' nutritional requirements (PC); a negative control diet reformulated to 80 kcal/kg less than the apparent metabolizable energy (AME) of the PC (NC1); a negative control diet reformulated to 120 kcal/kg less than the AME of the PC (NC2); an NC1 diet supplemented with 300 g/t of KZP (NC1 + KZP300); and an NC2 supplemented with 500 g/t of KZP (NC2 + KZP500). Growth performance was measured throughout the study. At 35 days, 10 birds per treatment were randomly selected and euthanized for a carcass trait evaluation, and samples of the duodenum were collected for morphological examination and pH level determination. The final average body weight and feed conversion ratio were better (p < 0.05) for the broilers in the NC1 + KZP300 group compared to those in NC1, NC2 and NC2 + KZP500 groups and were similar to those of the PC birds (p > 0.05). Birds from the NC1 + KZP500 group showed a better (p < 0.05) final body weight and feed efficiency compared to the NC1 and NC2 groups. The villus height was greater (p < 0.05) for the PC and NC1 + KZP300 groups compared to the rest of the treatments. The crypt depth was longer (p < 0.05) for the NC1 and NC2 groups compared to the NC1 + KZP300 group. The supplementation of KZP to both the NC1 and NC2 diets reduced (p < 0.05) the abdominal fat %. This study demonstrates that supplementing energy-reduced diets with KZP improved performance in broiler chickens.

Review: Composition and utilisation of feed by monogastric animals in the context of circular food production systems

Food production has a major impact on environmental emissions, climate change and land-use. To reduce this impact, the circularity of future food production systems is expected to become increasingly important. In a circular food system, crop land is primarily used for plant-based food production, while low-opportunity cost feed materials (LCF), i.e. crop residues, co-products of the food industry, grass from marginal land and food waste form the basis of future, animal feeds. Animal diets thus contain much less cereals and soybean meal and include a higher proportion of diverse co-products, residues and novel human-inedible ingredients. These diets are characterised by a lower starch content, and a higher content of fibre, protein, fat, and phytate compared to present diets. In this review, possible consequences of the development towards a more circular food system for the type, volume and nutritional characteristics of feed materials and complete feeds are addressed and related research questions in the area of animal nutrition, physiology and metabolism are discussed. Additional attention is given to possible effects on intestinal health and gut functionality and to (bio)technological processing of LCF to improve their suitability for feeding farm animals, with a focus on the effects in pigs and poultry. It is concluded that an increased use of LCF may limit the use of presently used criteria for the efficiency of animal production and nutrient utilisation. Development of characteristics that reflect the efficacy and efficiency of the net contribution of animal production in a circular food system is required. Animal scientists can have an important role in the development of more circular food production systems by focussing on the optimal use of LCF in animal diets for the production of animal-source food, while minimising the use of human-edible food in animal feed.

Effect of Lipase and Lysolecithin Supplementation with Low Energy Diet on Growth Performance, Biochemical Attributes and Fatty Acid Profile of Breast Muscle of Broiler Chickens

This study aimed to investigate the effect of dietary lysolecithin (LYSO) and lipase supplementation on productive performance, nutrient retention, and meat quality of broiler chicken fed a low energy diet. For this purpose, a total of 360 chicks were randomly alienated into six treatments, having six replicates (no = 10) birds each replicate. The dietary treatments were followed as control (CON fed as normal energy diet), LE (CON-100 kcal/kg from BD. basal diet), LIP 0.04 (LE + 0.04% lipase), LYSO 0.04 (LE + 0.04% lysolecithin), LIP + LYSO 0.04 (LE + 0.04% lipase and lysolecithin), and LIP + LYSO 0.08 (LE. + 0.08% lipase and lysolecithin). The birds fed with LIP + LYSO 0.04 exhibited higher weight gain than LYSO 0.08 and CON (p < 0.05), and higher feed intake (F.I.) was also observed in LIP + LYSO 0.04 than CON. However, lipase and emulsifier dietary effects were non-significant on FCR. (p > 0.05). Effects of experimental diets on dry matter (DM), crude protein (CP), and fat digestibility were also non-significant (p > 0.05). Similarly, the blood biochemical profile (total cholesterol, triglycerides, LDL, HDL) of the broiler showed no significant difference (p > 0.05) by dietary treatments. Similarly, liver enzymes, AST and A.L.T., were also not statistically significant (p > 0.05) among all dietary treatments. Similarly, supplementation of LIP and LYSO had a non-significant (p > 0.05) effect on breast meat fatty acids composition. Conclusively, adding LIP + LYSO 0.08 to a low energy diet could demonstrate better growth performance and reduce the negative impact of a low-energy diet.

Effect of dietary concentrations of metabolizable energy and neutral detergent fiber on productive performance, egg quality, fatty liver incidence, and hepatic fatty acid metabolism in aged laying hens

The objective of the current experiment was to investigate the effect of dietary concentrations of ME and neutral detergent fiber (NDF) on productive performance, egg quality, fatty liver incidence, and hepatic fatty acid metabolism in aged laying hens. A total of three hundred twenty 75-wk-old Hy-Line Brown laying hens were allotted to 1 of 4 dietary treatments with 8 replicates. Each replicate consisted of 10 consecutive cages with 1 hen per cage. The experiment was conducted using a completely randomized design with 2 × 2 factorial arrangement consisting of 2 levels of ME (normal [commercially recommended AME_n levels; 2,730 kcal/kg] and low [50 kcal/kg reduction in AME_n; 2,680 kcal/kg]) and 2 levels of NDF (low [9.01 and 9.61%; normal-ME and low-ME diets_, respectively] and high [12.57 and 13.42%; normal-ME and low-ME diets_, respectively]) in the diet. The diets and water were provided to hens on an ad libitum basis for 12 wk. Results indicated that no interactions between dietary concentrations of ME and NDF were observed for all measurements except for egg yolk color, eggshell thickness, and 2 hepatic gene expressions (i.e., carnitine palmitoyl transferase 1A and malic enzyme). For the main effects, increasing NDF concentrations in diets increased (P < 0.05) feed intake without affecting other productive performance. Hens fed normal-ME and high-NDF diets showed the darkest (P < 0.05) egg yolk color among those fed treatment diets, showing an interaction (P < 0.05). Increasing NDF concentrations in low-ME diets did not influence eggshell thickness, but those in normal-ME diets increased eggshell thickness in laying hens, showing an interaction (P < 0.05). For the main effects, increasing concentrations of dietary NDF or ME reduced (P < 0.05) hepatic fat concentrations with decreasing expressions in several genes related to fatty acid synthesis. In conclusion, increasing NDF concentrations in commercially-recommended ME diets decrease hepatic fat concentrations in aged laying hens, and therefore, may have a preventative effect on the fatty liver development in aged laying hens.

Xylanase supplementation of pelleted wheat-based diets increases growth efficiency and apparent metabolizable energy and decreases viscosity of intestinal contents in broilers

This study was designed to test graded supplementation of a thermostable xylanase in pelleted, wheat-based diets fed to broiler chickens over a 28-d period. A total of 600 Ross 708 male broilers were allotted to 1 of 5 dietary treatments: positive control (PC), negative control (NC; 125 kcal of AME/kg diet reduction relative to PC), and NC supplemented with 10, 15, or 30 g/ton of xylanase. Wheat-soybean meal-based diets were pelleted and fed in 2 feeding phases (14-d each). Study outcomes included growth performance, AME, and ileal digesta viscosity with 20 battery cages of 6 birds per treatment. Data were analyzed by 1-way ANOVA along with estimation of Pearson correlation coefficients. Whereas no difference between NC and PC was observed for BW gain, NC birds exhibited increased (P < 0.05) feed intake during each feeding phase and overall, which caused improvements (P < 0.05) in feed conversion ratio (FCR) for PC vs. NC birds. The analyzed AME of PC birds was 112 kcal/kg of diet greater (P < 0.05) than for NC birds, though no differences in digesta viscosity were observed. Xylanase supplementation of the NC diet at 15 or 30 g/ton elicited overall improvements (P < 0.05) in BW gain beyond the PC, while the 30 g/ton level equalized feed intake with the PC. Regardless of level, xylanase supplementation improved (P < 0.05) the FCR relative to the NC, thereby equalizing the response with the PC. Similarly, supplementation with any xylanase level increased (P < 0.05) AME over the NC, making all treatments synonymous with the PC. Digesta viscosity of all xylanase-supplemented treatments was decreased relative to both the NC and PC treatments. Overall, this study provided clear evidence that addition of a thermostable xylanase to pelleted wheat-based diets elicited improvements in growth performance of broilers concomitant with a reduction in digesta viscosity and elevation of analyzed dietary AME content.

Barley, an Undervalued Cereal for Poultry Diets: Limitations and Opportunities

Simple Summary

With the ever-increasing demand for poultry products, the continuous supply of conventional cereal grains such as maize has become a challenge. Barley has been recognised as a potential alternative feed ingredient that can replace common cereal grains in poultry diets. However, due to several limitations such as the presence of various anti-nutritive factors and the variability in nutrient composition and quality, the use of barley in poultry diets remains comparatively low. The previous findings on the optimum use of barley in poultry diets are also inconsistent primarily due to differences in research methodologies. The importance of using accurate nutrient profiles for specific barley cultivars to formulate barley-based diets is emphasised in this review. Moreover, the need to adapt feed processing conditions suitable to different barley cultivars to increase the inclusion of barley in poultry diets is highlighted in this review.

Abstract

The supply of conventional cereal grains, especially of maize, will be a significant constraint to the future growth of the poultry industry. Various alternative feed ingredients are being tested to replace maize in poultry diets. Barley (Hordeum vulgare L.) is one such feed ingredient, the use of which remains limited in poultry diets due to its low metabolisable energy, presence of anti-nutritive, soluble non-starch polysaccharides and consequent inter-cultivar variability. Differences in research methodologies used in published studies have also contributed to the inconsistent findings, preventing a good understanding of the nutritional value of barley for poultry. The importance of using accurate nutrient profiles, specifically metabolisable energy and digestible amino acids, for specific barley cultivars to formulate barley-based diets is emphasised. Nutritionists should also pay close attention to feed processing conditions tailored to the specific barley cultivars to increase the barley inclusion in poultry diets.

Effects of Chitosan Oligosaccharide on Production Performance, Egg Quality and Ovarian Function in Laying Hens with Fatty Liver Syndrome

Simple Summary

Fatty liver syndrome (FLS) often occurs in caged laying hens and can cause decreases in production performance. Chitosan oligosaccharide (COS), degraded from chitin or chitosan, has been demonstrated to prevent metabolic diseases in rodents. In this work, we found that dietary COS supplementation could improve production performance and egg quality in laying hens with FLS. Further study indicated that improved ovarian morphology and function may be involved in these beneficial effects of COS. Specifically, dietary COS supplementation decreased oxidative stress, inflammation and apoptosis in the ovaries of laying hens with FLS. This study provides evidence for the application of COS to improve production performance and egg quality in laying hens with FLS.

Abstract

This study aimed to investigate the role of chitosan oligosaccharide (COS) as an additive in the feed of laying hens with fatty liver syndrome (FLS). Effects on production performance, egg quality as well as ovarian function were determined. A total of 360 Lohmann Pink-shell laying hens (28 weeks old) were randomly assigned to 5 groups (6 replicates × 12 birds). Hens were fed with a basal diet and a high-energy low-protein (HELP) diet supplemented with 0, 200, 400 and 800 mg/kg COS. COS reversed the lowered laying rates, increased feed-to-egg ratios and decreased albumen heights and Haugh units induced by the HELP diet. Additionally, COS improved the ovarian morphologies damaged by the HELP diet. Furthermore, COS enhanced antioxidant enzyme activities, reduced malonaldehyde levels and downregulated the mRNA expressions of nuclear factor kappa B, pro-inflammation cytokine genes and pro-apoptosis-related genes, while it upregulated the mRNA expression of anti-apoptosis-related genes in the ovaries of HELP-diet-fed hens. These findings suggested that dietary COS supplementation could improve production performance and egg quality in laying hens with FLS, and these beneficial effects were linked to improved ovarian morphology, which was attributed to decreased oxidative stress, inflammation and apoptosis in the ovaries.

The effect of gradually decreasing the dietary energy content, at constant or increased lysine:energy ratio on broiler performance, carcass yield, and body composition

Formulating diets with high AME, especially in the grower and finisher phases, hinders the inclusion of alternative ingredients that are usually cheaper and have lower AME. Moreover, as the chicken grows the feed intake capacity is greater and may be able to maintain BW over a wide range of AME. The objective of this study was to evaluate the performance of chickens fed diets with progressive AME reductions, at constant or increased standardized ileal digestible (SID) lysine:AME ratio (Lys:AME). Treatment 1 (control) was formulated following the SID lysine and AME recommendations for a 4-phase feeding program. Treatment 5 was formulated with -4, -8, and -12% AME in the grower-1, grower-2, and finisher phases, respectively, and with the same Lys:AME compared with the control. Treatment 9 had the same AME as treatment 5 but higher SID lysine, increasing the Lys:AME by 1.5, 3.5, and 5.0% compared with treatment 5. In the grower-1, grower-2, and finisher phases, the final 9 dietary treatments were prepared by mixing the control diet with either treatment 5 or 9 at different proportions (75:25, 50:50, or 25:75). All birds were fed the same starter control diet. Treatments were replicated in 10 pens with 31 male chickens each, and the growth performance of birds was monitored for 42 d. Final BW linearly decreased (P < 0.05) when lowering dietary AME, but it followed a positive quadratic response with higher Lys:AME (P < 0.05). Feed intake increased (P < 0.05) with low AME, independently of the Lys:AME; but the linear regression in the feed conversion ratio (FCR) had a lower slope when the Lys:AME increased. At the end of the study, there were no differences in carcass or breast meat yield (P > 0.10). Progressively reducing AME in the last feeding phases may be a viable nutritional strategy to increase the inclusion of alternative ingredients and potentially reduce feeding costs, despite increments in feed intake and FCR. Adjusting the Lys:AME in low AME diets may help maintain the final BW of birds.

Gut microbiota activity in chickens from two genetic lines and with outdoor-preferring, moderate-preferring, and indoor-preferring ranging profiles

Despite the existing research into the gut microbiome of meat chickens, the associations between gut microbiome composition, its activity and chicken outdoor ranging frequency remain unexplored. The aim of this study was to determine the gut microbiota composition, activity and metabolic products in chickens of 2 different lines and 3 ranging profiles. Sixty non-beak trimmed birds, either Sasso or Green-legged Partridge were housed with access to outdoor ranges from wk. 5 to 10 of age. Outdoor ranges were video recorded to obtain frequencies of the birds’ range use. The information about relative abundance of selected bacterial groups in the ceca including Lactobacillus spp., E. coli, Bifidobacterium spp., and Clostridium spp. was obtained with the PCR method. Gut microbiota activity was assessed based on the glycolytic activity of bacterial enzymes including, α-glucosidase, β-glucosidase, α-galactosidase, β-galactosidase, and β-glucuronidase as well as based on the concentration of short-chain fatty acids (SCFA) in the caecal digesta. Statistical analysis was conducted by generalized linear mixed models, applying the breed and ranging profile as fixed effects and pen as a random factor. The lowest relative abundance of Bifidobacterium spp. was found in the cecal content of indoor-preferring Sasso birds (0.01 ± 0.001), as compared to all other birds in the experiment (ranging from 0.03 ± 0.01 to 0.11 ± 0.07; P = 0.0002). The lowest relative abundance of E. coli was identified for all outdoor-preferring birds and indoor- preferring Sasso birds (0.01 ± 0.001; P = 0.0087). Cecal activity of: α-glucosidase, β-glucuronidase and β-galactosidase was higher in Green-legged Partridges, as compared to Sasso (P = 0.013; P = 0.008; P = 0.004). Valeric acid concentrations were higher in moderate Green-legged Partridges than in Sasso of the same ranging profile (2.03 ± 0.16 vs. 1.5 ± 0.17; 0.016). The majority of the current results confirmed an effect of genotype and ranging profile on the various analyzed parameters. In outdoor-preferring birds, the consumption of pasture originating feed sources as a supplement to the indoor accessible cereal-based diet likely caused the positive effects on the birds’ microbial profile.

Exogenous emulsifiers and multi-enzyme combination improves growth performance of the young broiler chickens fed low energy diets containing vegetable oil

Objective

The present study examined the effects of exogenous emulsifiers and multi-enzyme supplementation into a low energy density diet on growth performance, visceral organ parameters, blood metabolites, ileal morphology, and nutrient digestibility in broiler chickens from hatch to 21 days.

Methods

One hundred and sixty-eight one-day-old Ross 308 broiler chickens were allocated in a completely randomized design to 24 pens and each pen was assigned to one of four dietary treatments to give six replications with seven chickens in a cage. Dietary treatments were: i) positive control with standard energy level (PC); ii) negative control with 100 kcal/kg lower energy of the standard level (NC); iii) NC diet supplemented 0.05% calcium stearoyl-2 lactylate as an emulsifier (NC+E); and iv) NC diet supplemented with both 0.05% calcium stearoyl-2 lactylate and 0.05% multi-enzyme (NC+E+M). Corn and soybean meal-based control diets containing vegetable oil were formulated to meet the Ross 308 nutrition specification. Chickens were fed ad-libitum with the treatment diets and sampling was conducted on day 21.

Results

Our results revealed that emulsifier and multi-enzyme supplementation into NC diets improved (p<0.05) feed efficiency of the broiler chickens compared to the broiler chickens fed NC diets from hatch to 21 days. Supplementation of emulsifier and multi-enzyme into NC diet improved (p<0.05) nutrient digestibility of the broiler chickens. However, emulsifier and multi-enzymesupplementation into diet did not influence (p>0.05) visceral organ weight, blood metabolites, and intestinal morphology in broiler chickens fed NC diets.

Conclusion

Supplementation of emulsifier and multi-enzyme in the NC diet would support improving growth performance in young broiler chickens with improved feed efficiency and increased nutrient digestibility thereby curtailing the negative impact of energy reduction in the diets.

Soybean vs. Pea Bean in the Diet of Medium-Growing Broiler Chickens Raised under Semi-Intensive Conditions of Inner Mediterranean Areas: Growth Performance and Environmental Impact

The effects of Glycine max L. (SOY) vs. Pisum sativum L. (PEA) in the diet were investigated on in vivo performance of two medium-growing broiler genotypes and on environmental impact. Sixty Kabir Red Plus and sixty New Red chickens were randomly allocated in 20 pens (n = 6 birds per pen). Each pen, i.e., experimental unit, received 1.18 kg dry matter (DM) including soybean (3.39%) in SOY, or pea bean (6.78%) in PEA groups. DM intake, DM refusals and bodyweight (BW) were recorded on pen basis, and average daily gain (ADG) and feed conversion rate (FCR) were calculated. Data on in vivo performance were processed by ANOVA General Linear Model followed by Student−Newman−Keuls post hoc test. Greenhouse gas (GHG) emissions were evaluated on a year basis by GLEAM-i software. The diet did not affect (p > 0.05) DM intake and DM refusals, BW, ADG and FCR. Diet x genotypes affected (p < 0.05) DM intake and DM refusals. PEA diet, cheaper than SOY diet, allowed the reduction in total GHG and CO2, and of meat emission intensity. However, an increase in total CH4 and N2O emissions was observed. The replacement of soybean with pea bean can represent a possible management strategy to reach trade-off between good farming practices and environmental protection on small-scale poultry farms of inner Mediterranean areas.

The Impact of Genotype and Age on Energy and Protein Utilization in Individually Housed Brown Laying Hens

Simple Summary

An investigation into whether the nutrient requirement of egg-laying hens has changed with genotype improvements was conducted. This study compared the response of individually housed laying hens of two different genotypes and ages. The strains used were a heritage breed in mid-lay and a modern breed at peak production. Energy was utilized with the same efficiency by both strains. All hens were able to adjust their feed intake to ensure that their energy requirements were met. The modern strain utilized protein slightly more efficiently than the heritage strain. It is unlikely that the nutrient requirements of modern layer strains have increased. More likely, requirements have decreased because modern hens are lighter and have a lower daily egg output (lay smaller eggs) despite their higher lifetime egg output. Regardless, feeding programs need to be adjusted for economic reasons and depend on achievable feed intakes under particular circumstances.

Abstract

Responses to dietary energy and protein levels were compared between two egg-laying genotypes. Individually housed hens of a historic strain (HS) and a modern strain (MS) were compared. In Experiment 1 (Exp.1), four levels of true metabolizable energy, corrected for zero nitrogen retention (TME_n) and four levels of total lysine, were offered from 30 to 40 weeks of age. In Experiment 2 (Exp.2), three levels of apparent metabolizable energy, corrected for zero nitrogen retention (AME_n) and four levels of standardized ileal digestible lysine (SID Lys), were fed from 20 to 30 weeks of age. A randomized factorial block design (4 × 4 Exp.1 and 3 × 4 Exp.2) was applied. Energy utilization for egg output (EO) did not differ (NS), and both strains maintained a constant kJ intake (NS). The efficiency of SID Lys utilization for EO differed, with the MS being the more efficient (p < 0.034). A single model could be used to predict feed intake, using BW, EO, AME_n and SID Lys (r = 0.716). In conclusion, it is unlikely that the requirements of modern layer strains have increased. However, feeding programs should be adjusted for economic reasons and are dependent upon achievable feed intake under particular circumstances.

Towards the prediction of feed intake capacity of modern broilers on bulky feeds

The use of alternative, often bulky ingredients is becoming widespread in poultry diets as the industry seeks to reduce its economic and environmental costs. Consequently, there is an increased need to accurately predict the performance of birds given such diets and identify their maximum capacity for bulk. We offered diets diluted with a range of bulky ingredients to male Ross 308 broilers to assess their capacity for bulk and identify a bulk characteristic responsible for limiting intake. Four hundred ninety-five day-old broilers allocated into 45 pens, were offered a common starter diet until day (d) 7, and 1 of 9 grower diets from d 8 to 29 (Period 1). Each of the grower diets was diluted with either 30 or 60% of oat hulls (OH), wheat bran (WB), or grass meal (GM), or a mixture of 2 bulky ingredients at an inclusion level of 30% each (OHWB, OHGM, WBGM). From d 29 to 43 (Period 2), all birds were offered the bulkiest diet (GM60). A number of bulk characteristics were measured on the diets. Feed intake was measured daily, and birds were dissected on d 29 and 43 for organ and carcass measurements. During d 8 to 14 diet water-holding capacity (WHC) was more consistent in predicting feed intake when scaled per unit of body weight than any other bulk characteristic. However, this was no longer the case during d 15 to 28. In Period 2, the response and adaptation to the bulkiest diet was determined by previous experience to bulk. Birds offered a bulkier diet during Period 1, were better able to adapt the size of their digestive organs and increase scaled feed intake, such that there were no differences between these birds and those offered the GM60; the converse was the case for birds on the least bulky diets. We conclude that WHC is able to predict maximum intake on bulky diets in unadapted birds. Adaptation to bulky diets can be very fast, so that their high bulk content no longer limits feed intake and performance.

Supplementation of Bile Acids and Lipase in Broiler Diets for Better Nutrient Utilization and Performance: Potential Effects and Future Implications – A Review

Bile acids are used for better emulsification, digestion and absorption of dietary fat in chicken, especially in early life. Similarly, exogenous lipases have also been used for the improvement of physiological limitation of the chicken digestive system. Owing to potential of both bile acids and lipases, their use has been increased in recent years, for better emulsification of dietary fat and improvement of growth performance in broilers. In the past, pancreatic lipases were used for supplementation, but recently, microbial lipase is getting attention in poultry industry as a hydrolysis catalyst. Bile acids strengthen the defence mechanism of body against bacterial endotoxins and also play a key role in lipid regulation and sugar metabolism as signaling molecules. It has been demonstrated that bile acids and lipases may improve feed efficiency by enhancing digestive enzyme activity and ultimately leading to better fat digestion and absorption. Wide supplemental range of bile acids (0.004% to 0.25%) and lipases (0.01% to 0.1%) has been used in broiler diets for improvement of fat digestibility and their performance. Combinations of different bile acids have shown more potential to improve feed efficiency (by 7.14%) even at low (0.008%) levels as compared to any individual bile acid. Lipases at a lower level of 0.03% have exhibited more promising potential to improve fat digestibility and feed efficiency. However, contradicting results have been published in literature, which needs further investigations to elucidate various nutritional aspects of bile acids and lipase supplementation in broiler diet. This review focuses on providing insight on the mechanism of action and potential application of bile acids and lipases in broiler diets. Moreover, future implications of these additives in poultry nutrition for enhancing nutrient utilization and absorption are also discussed.

Dietary metabolizable energy, digestible lysine, available phosphorus levels and exogenous enzymes affect broiler chicken performance

The nutritional composition of diets and the provision of exogenous enzymes play important roles in animal performance. Here, we evaluated the individual and combined impact of nutrients (metabolizable energy (ME), digestible lysine (dLys), available phosphorus and calcium (avP-Ca)) and exogenous multicarbohydrase and phytase complex (MCPC) enyzmes on the growth performance and feed efficiency of broiler chickens from 10 to 42 days (d) of age. Experimental diets were formulated in a Box-Behnken design to contain various levels of ME (11.89, 12.21, 12.54 or 13.06 MJ/kg), dLys (0.91%, 0.93%, 0.96% or 1.00%) and avP/Ca (0.12/0.47%, 0.21/0.58% or 0.33/0.68%). The effect of MCPC was expressed in terms of the extra nutrients released. The diets were formulated to have consistent substrate contents (i.e., arabinoxylan and phytate). Feed intake (FI), BW gain (BWG) and feed conversion ratio (FCR) were described via polynomial equations (R² = 0.99, 0.98 and 0.81, respectively), with interconnections between variables (ME, dLys and avP-Ca). Available P-Ca was the most important factor affecting FI (quadratically), and BWG and FCR (linearly). Reducing the avP content from 0.33% to 0.12% in diets lacking MCPC resulted in 25% and 33% decreases in FI and BWG, respectively, and a 12% increase in FCR. The ME and dLys contents also linearly affected these performance parameters to a lesser degree; FI decreased by 400 g when the ME was reduced by 1.17 MJ/kg, and by 300 g following a 0.09% reduction of dLys, while the same reductions in ME and dLys decreased BWG by 120 g and 150 g, respectively. The inclusion of MCPC alleviated the reduction of FI, BWG and FCR by decreasing the avP-Ca. Thus, ME and dLys were the most important factors affecting BWG and FCR in broilers fed diets containing MCPC. When MCPC was added, ME negatively affected FI (r = -0.89, P < 0.001), whereas the dLys content was correlated with BWG (r = 0.74, P < 0.001). Both ME and dLys affected FCR (r = -0.83 and -0.85, respectively). Supplementing MCPC allowed the reduction of ME, dLys and avP-Ca in the diet without affecting performance. Indeed, MCPC's effect promoted with the release of the following nutrients: 0.56 MJ ME/kg, 0.06% dLys, and 0.15% and 0.13% avP and Ca, respectively. The results indicate nutrient effect and interaction on performance and feed additive potential for nutrient release.

Net energy, energy utilization, and nitrogen and energy balance affected by dietary pea supplementation in broilers

Pea starch consists predominantly of C-type of amylopectin chain which is more resistant to digestive enzymes than A-type of starch thus slowly digested in poultry. It was hypothesized that the presence of slowly digested pea starch in broiler diets will increase net energy and the efficiency of energy utilization in broilers. Two experiments were performed to investigate starch digestibility of pea at different incubation times (in vitro study) and the effect of dietary pea on heat increment and net energy in broilers using an open-circuit respiratory calorimetry system (in vivo study). One-day-old Ross 308 male broilers were fed a common starter crumble from d 1 to 10 and standard grower diets thereafter. At d 21, birds were transferred to the chambers each housing 2 birds. Each treatment was replicated 6 times with 2 identical runs of 3 replicates per treatment. A wheat-soybean meal-based diet was used as a control and the treatment diet contained 500 g of pea/kg pea. In vitro study showed that pellet processing increased (P < 0.001) starch digestibility, particularly at shorter times for wheat and a much larger response for pea. Birds offered the pea-based diet had lower (P = 0.002) feed intake, lower (P = 0.020) body weight gain, but a similar (P > 0.05) FCR compared to those offered the wheat-based diet. Net energy (NE) and apparent metabolizable energy (AME) values were higher in the pea-based diet than in the wheat-based diet (P = 0.037 for NE and P = 0.018 for AME). Heat production, respiratory quotient, heat increment of feed, efficiency of utilization of gross energy for AME, and efficiency of utilization of AME for NE did not differ (P > 0.05) between the 2 treatments. There was no effect (P > 0.05) of pea on the total tract digestibilities of dry matter, crude protein and ash, but the total tract digestibility of starch was higher (P = 0.022) in the pea-based diet compared to the wheat-based diet. This study provides insight into the energy metabolism of broilers offered a pea-based diet and indicates that dietary pea supplementation increases dietary AME and NE but has no effect on heat increment of feed and the efficiency of energy utilization in broilers.

Effect of Broilers Chicken Diet Supplementation with Natural and Acidified Humic Substances on Quality of Produced Breast Meat

Simple Summary

Meat quality can be influenced by incorporating additives into an animal’s diet. Humic substances (HS) are natural products which have the potential to improve the meat quality of broiler chickens. HS are used as antidiarrheal, analgesic, immunostimulatory, and antimicrobial agents in poultry production. The effects of natural and acidified HS supplements on broiler meat quality traits (growth performance, carcass yield, physicochemical composition, lipid oxidation, antioxidant activity of meat extracts, and sensory and colour characteristics) were studied. Both supplements were composed of Leonardite, whereby the acidified HS were treated with formic acid for better digestibility. The breast meat quality of experimental broiler groups fed with HS were affected in total protein and fat content, and both showed lower lipid oxidation and higher antioxidant activity of meat extracts after the storage period (7 days at 4 ± 2 °C).

Abstract

This study was conducted to examine the effect of two humic substances (HS) supplemented in broilers’ diet on the breast meat quality of broiler chickens. In this experiment, 120 pieces of one-day-old COBB500 broiler chickens were used. Broilers were divided into three groups, each containing 40 birds with three replications (13, 13, and 14 per one pen). Fattening lasted 38 days. The first experimental diet was supplemented with 0.7% of HS (HS0.7) and the second was enriched with 0.7% of acidified HS (HSA0.7). The control group of broilers (C) was fed a basal diet without the addition of any supplements. HS0.7 samples had the highest total protein content and the lowest content of fat (p < 0.01). The effects of broiler diet and storage had a significant impact on the pH of breast samples, p < 0.001 and p < 0.05, respectively. Supplementation of HS in broiler diet positively affected the lipid oxidation of breast meat samples, as indicated by the lower malondialdehyde content (p < 0.05). HSA0.7 samples had significantly better juiciness after the storage period (p < 0.001). The quality of meat produced with supplementation of HS in broilers’ feed can be considered as valuable in human nutrition due to improved protein and fat content with decreased lipid oxidation.

Balanced nutrient density for broiler chickens using a range of digestible lysine-to-metabolizable energy ratios and nutrient density: Growth performance, nutrient utilisation and apparent metabolizable energy

Currently, specific nutrient concentration, metabolizable energy (ME) and digestible amino acids are used as feed formulation criteria. A balanced nutrient density (BND) concept based on 2 criteria of nutrient density and balanced amino acids-to-ME ratio may offer more flexibility in optimisation of profit in formulation of diets compared with current formulation based on set values per unit of feed mass. A total of 672 one-d-old off-sex male Ross 308 broiler chickens were used across two 42-d performance trials in a 3 × 2 factorial arrangement of treatments with each diet replicated 8 times (14 birds per replicate). The experimental factors were 2 nutrient density levels (low [LD] and high [HD]) and 3 digestible lysine-to-ME ratios (DLYS:ME; low, medium, and high). Low density diets had ME of 2,876 and 3,023 kcal/kg for starter and finisher, respectively, while values for HD diets were 3,169 and 3,315 kcal/kg with proportionally higher non-nitrogenated nutrients. Separate digestibility and apparent metabolizable energy (AME) assays were conducted at d 21 and 42. Digestibility assays at d 7 were conducted on birds used for performance trials. Regardless of the diet density, birds fed low DLYS:ME had a lower (P < 0.01) feed intake (d 0 to 42) than medium and high DLYS:ME. Without interaction, birds fed low and medium DLYS:ME had a similar body weight gain being the heaviest while birds low DLYS:ME were the lightest. By an interaction (P < 0.05), the highest overall FCR value was observed for birds fed LD × low DLYS:ME and improved linearly when DLYS:ME increased to the highest level reaching a limit for birds fed HD × medium DLYS:ME. Calorie conversion linearly decreased (P < 0.001) with increments in DLYS:ME. Jejunal and ileal starch and protein digestibility were affected on d 21 and 42 but not on d 7 of age. Given the independence of response on BW and feed consumption, the use of BND as a flexible system in diet formulations has the potential to enable more accurate formulation for optimisation of growth performance of broiler chickens.

Astaxanthin supplementation enriches productive performance, physiological and immunological responses in laying hens

Objective

Astaxanthin is a natural super antioxidant. The present study was carried out to investigate the effect of astaxanthin rich Phaffia rhodozyma (PR) supplementation in diets on laying production performance, egg quality, antioxidant defenses and immune defenses in laying hens.

Methods

A total of five hundred and twelve 60-week-old Lohmann Brown laying hens (2,243±12 g) were randomly assigned to four groups, each including 4 replicates with 32 birds per replicate. Astaxanthin rich PR was added to corn-soybean meal diets to produce experimental diets containing 0 (Control), 800 mg/kg, 1,200 mg/kg, and 1,600 mg/kg PR, respectively. The astaxanthin content in the diet was 0.96 mg/kg, 1.44 mg/kg and 1.92 mg/kg respectively.

Results

Results showed that dietary PR supplementation tended to increase daily feed intake (p = 0.0512). There was no effect of astaxanthin rich PR on Haugh units, albumen height, egg shape index, eggshell strength, and eggshell thickness at weeks 6 (p>0.05). However, egg yolk color was significantly improved (p<0.05). In addition, astaxanthin rich PR supplementation significantly increased serum glutathione peroxidase and superoxide dismutase activity (p<0.05), increased serum immunoglobulin G content (p<0.05), and reduced malondialdehyde content (p<0.05) in laying hens.

Conclusion

In conclusion, astaxanthin rich PR can improve the color of egg yolk, enhance the antioxidant defenses, and regulate the immune function.

What are the limits to feed intake of broilers on bulky feeds?

The view that genetic selection for carcass yield has limited the size of the gastrointestinal tract (GIT) of modern broilers has sparked concerns that their capacity to cope with energy dilution or bulk is also limited. We investigated the capacity of male Ross 308 broilers to deal with increasing levels of bulk and aimed to identify a feed bulk dimension responsible for limiting feed intake (FI). About 528 day-old broilers were allocated to 48 pens and offered a common starter feed until day 8, and 1 of 7 feeds from day 8 to 36 of age: a basal control (B), which was diluted to 3 levels (15, 30, or 45%) with either oat hulls (OH) or sugar beet pulp (SBP). Feed intake was measured daily and birds were dissected for GIT measurements at day 15, 22, and 36. Feed intake increased in birds offered OH15 (135 g/d), OH30 (140 g/d), and SBP15 (138 g/d) compared with birds offered the B feed (106 g/d; SEM 2.4). By increasing FI, birds were able to compensate for the lower energy content of their feeds. The greatest increase in FI was seen on OH30: its energy content (2,273 kcal/kg) was 26% lower than the B feed (3,081 kcal/kg). There was evidence of adaptation on the bulky feeds, as during the last week only birds on SBP45 were limited in FI and performance. The relative weights of the GIT were greater in the SBP than OH series, suggesting that the former needed to accommodate a higher bulk intake. For the OH series the increase in the relative GIT weights was confined to the gizzard and small intestine; whereas for the SBP series, the increase was extended to proventriculus and large intestine. Because only SBP45 was limiting FI, we were unable to identify a bulk dimension to be used to predict FI. Our data reject the suggestion that modern broilers have a reduced ability to cope with reductions in feed energy content.

Effects of dietary probiotic (Pediococcus acidilactici) supplementation on productive performance, egg quality, and body composition in laying hens fed diets varying in energy density

This study was conducted to determine the effect of probiotic Pediococcus acidilactici (PA) strain MA18/5M supplementation of diets with different dietary energy levels on productive performance, egg quality, and body composition in Hy-Line Brown hens during a 16-week period from 32 to 47 wk of age. The experimental treatments with a 2 × 2 factorial design received a 2 wheat–corn–soybean diet: a moderately low energy density diet with 2,650 kcal ME/kg (M-LED) and a low energy density diet based on the M-LED diet with 2,550 kcal ME/kg (LED), each diet without and with probiotic supplementation (M-LED, LED, M-LEDp, and LEDp, respectively). Reduced dietary energy levels had a particularly negative effect on egg weight (61.7 vs. 63.3 g; −2.6%, P < 0.001), egg mass output (1.67 vs. 1.71 kg; −2.4%, P = 0.015), and FCR (2.01 vs. 1.97 kg feed/kg egg; +2%, P = 0.028). In hens administered the LED diet, deteriorated productive performance was accompanied by greater body weight loss (P < 0.001) and reduced abdominal fat content (P < 0.033) as compared with the M-LED group. Dietary probiotic inclusion increased egg weight (P = 0.015), including relative eggshell weight (P = 0.008) and eggshell thickness (P = 0.002) and significantly improved FCR (P = 0.010). No interactions between the PA-based probiotic and dietary energy levels were found in any of the tested parameters. Adding the probiotic on top of the M-LED diet improved layers performance but resulted in nonbioequivalence for the egg weight, egg mass output, and FCR compared with this group without probiotic. Probiotic supplementation of the LEDp diet improved all performance parameters except for egg weight. As a result, the laying rate, egg mass output, daily feed intake, and FCR in the LEDp treatment were bioequivalent to those noted in the M-LED group without the probiotic. The results of a bioequivalence test suggest that a low energy diet fed to laying hens promoted a probiotic response to improve energy utilization by birds.

Effects of feed form and energy levels on growth performance, carcass yield and nutrient digestibility in broilers

Feed form is well recognized to improve broiler performance, specially by increasing feed intake (FI). However, when different diet energy levels are used, the results differ in the literature. Therefore, this experiment was conducted to evaluate the influence of feed form and dietary metabolizable energy (ME) levels on broiler performance, carcass yield and on the digestibility of DM, CP, starch and gross energy. In total, 1152 male Cobb 500 broilers were evaluated between 35 and 47 days. The birds were distributed according to a completely randomized design in a 2 × 4 factorial arrangement, consisting of two feed forms (mash or pellet) and four ME levels (12.73, 13.06, 13.40 or 13.73 MJ/kg), totaling eight treatments with eight replicates of 18 birds. Broilers fed the lowest ME level presented the lowest weight gain (WG) and worst feed per unit gain (P < 0.01). Metabolizable energy intake increased (P < 0.01) with progressive increments of ME, which, however, did not affect caloric conversion (CC, P > 0.05). Pelleted diets promoted higher FI, WG, ME intake (P < 0.01) and better feed per unit gain and CC (P < 0.05) compared with mash. In mash diets, increasing dietary ME levels promoted a linear increase in WG (P < 0.01) and reduced feed per unit gain (P ≤ 0.05), but did not affect FI (P > 0.05). In pelleted diets, on the other hand, increasing ME levels linearly reduced FI (P < 0.05) and feed per unit gain (P < 0.01). Broilers fed pelleted diets presented higher abdominal fat deposition than those fed mash (P < 0.05). Increasing ME levels reduced the coefficients of ileal apparent digestibility of DM (P < 0.01) and total starch (P < 0.05) but did not affect the digestibility of other evaluated nutrients. The digestibility of all nutrients was lower when pelleted diets were fed compared with mash. Increasing inert material inclusion in the diets at the expense of soybean oil to reduce dietary ME levels promoted higher pellet durability index values (P < 0.05) and the percentage of fines (P < 0.01). Overall, the results suggest that pelleted diets promote better broiler performance because they increase FI, since the digestibility of dietary fractions is reduced. Chickens consuming low-energy pelleted diets may increase FI to compensate for energy deficit. In contrast, broilers fed mash diets may have reached their maximum intake capacity and did not regulate FI by changing feed energy density. When feeding pelleted diets, dietary energy reduction should be considered to reduce feed costs and to improve the carcass quality of broilers.

Effect of rate and extent of starch digestion on broiler chicken performance

Dietary starch with lower rate and extent of digestion improves broiler feed efficiency, but previous results might have been confounded by non-starch components of the grains. Therefore, the objective of this research was to study the effects of starch digestion on broilers using semi-purified starch. Semi-purified wheat (WS, rapidly digested) and pea (PS, slowly digested) starch were combined to create 6 WS:PS ratios (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100) in starter, grower and finisher diets. Each treatment was fed to Ross 308 male (2,124) and female (2,376) broilers housed in 72 L floor pens from 0 to 31 d of age to measure performance and meat yield relative to live weight. On day 33, the effects of diet on 8 h feed withdrawal was assessed in 20 males per treatment. Data were analyzed with ANOVA and linear and quadratic regression analyses using SAS 9.4. Significance was accepted at P ≤ 0.050. Body weight gain declined linearly with increasing PS. Male feed intake decreased with increasing PS, but PS did not affect female feed intake. Mortality corrected gain:feed ratio was quadratically influenced by diet (estimated maximum at 25% PS). Breast meat increased linearly with PS, while fat pad and breast and thigh skin decreased linearly. Quadratic responses were found for thigh meat and whole drum (estimated maximum values at 56 and 54% PS, respectively). Males grew faster, ate more, and had higher mortality than females. They also had heavier pectoralis major, thigh bone, and whole drum, while females had heavier pectoralis minor and more breast and thigh skin. After feed withdrawal, digesta content decreased linearly with time in all sections, except for the crop and duodenum, which declined quadratically. Ileal digesta pH increased linearly with time, while crop and caecal pH decreased for 2 h before steadily increasing. Diet did not affect digestive tract emptying or digesta pH. In conclusion, dietary PS maximized feed efficiency at 25% PS and linearly improved breast meat yield, but did not affect digesta clearance after feed withdrawal.