Physical and nutritional effects of pelleting of broiler chicken diets made from wheat ground to different coarsenesses by the use of roller mill and hammer mill

Efficacy of maize differing in particle size in low-density protein diets fed to broilers from day 1 to 21 of age

1. This study evaluated the efficacy of maize differing in particle size in low-density protein diets on performance, the digestive tract and litter characteristics in broilers. Four dietary treatments; control commercial diet with a typical crude protein content 22.50% (CON); CON + 20% maize with particle size 350 µm (M350), crude protein 19.90%; CON + 20% maize with particle size 2600 µm (M2600), crude protein 19.90%); CON + 20% whole maize (WM), crude protein 19.90%, were fed ad libitum to broiler chicks up to 21 d of age.2. No differences in body weight gain, feed intake and FCR were found between the WM and CON. WM increased body weight gain compared to M350 and M2600. M350, M2600 and WM increased (p = 0.004) gizzard relative weight compared with CON on day 14. Both WM and M2600 reduced (p = 0.001) gastric isthmus diameter on d 14 and 21 compared with CON and M350.3. No differences were seen in mucosa for the Lamina propria and the extent of Tunica muscularis of gizzard on d 21 and ileum mucosal depth on d 14 between WM and CON diets. However, WM reduced villus-to-crypt ratio compared with CON on d 21. The M350 reduced (p < 0.05) gizzard digesta particle size compared with CON, M2600 and WM on d 14.4. Both WM and M350 decreased (p < 0.05) nitrogen excretion compared to birds fed CON. Feeding WM increased nitrogen efficiency compared with M350 and M2600 diets, but was similar to birds fed CON. Feeding M350, M2600 or WM decreased (p < 0.05) litter moisture and footpad dermatitis (FPD) scores compared with results from birds fed CON.5. Overall, diluting the protein level in broiler diets with whole maize appeared better than fine or coarse maize in terms of growth performance, digestive tract development, nitrogen excretion and litter parameters. This may lead to economic benefits by reducing grinding costs and dependence on rich protein resources contributing to sustainable meat production and food security.

Feed form and perch design do not interact to production performance, gastrointestinal tract traits, behaviour and welfare of laying hens reared in enriched cages

1. It was hypothesised that perch material and design may affect utility and maintenance energy demand in laying hens, affecting their feed form preferences and daily feed consumption. Accordingly, perch design and feed form on hen performance, gastrointestinal tract functions and some behavioural and welfare-related traits were studied in laying hens (ATAK-S) reared in enriched colony cages from 24 to 40 weeks of age.2. The experiment was a 2 × 2 factorial investigating two perch materials and design (circular steel or mushroom-shaped plastic) and feed form (mash or crumble). A total of 396 hens were randomly assigned to one of the four treatment groups with nine replicates each (11 birds per replicate).3. Except for feeding behaviour and prevalence of foot pad dermatitis at 40 weeks of age, the modification of the perch design did not have a significant effect on the traits examined. Mushroom-shaped plastic perches reduced feeding behaviour (p < 0.01) and the incidence of foot pad dermatitis at 40 weeks of age (p < 0.001).4. Performance traits were not affected by feed form. Intake, final body weight and FCR for crumble-fed laying hens were greater than those fed mash (p < 0.01).5. Hens fed mash had higher (p < 0.01) relative gizzard weights along with lower (p < 0.05) pH values, pancreatic chymotrypsin, amylase and lipase activities (p < 0.05), and duodenal absorption surface areas (p < 0.01). Ultimately, this gave higher protein digestibility (p < 0.05) compared to those receiving crumble.6. In conclusion, in enriched cage rearing systems, mashed feed was preferred over crumble to efficiently maintain productive performance. Compared to circular steel, plastic mushroom-shaped perches were associated with better footpad health and welfare.

Dietary fibre effects and the interplay with exogenous carbohydrases in poultry nutrition

A comprehensive understanding of the role of dietary fibre in non-ruminant animal production is elusive. Equivocal and conflated definitions of fibre coupled with significant analytical complexity, interact with poorly defined host and microbiome relationships. Dietary fibre is known to influence gut development, feed intake and passage rate, nutrient absorption, microbiome taxonomy and function, gut pH, endogenous nutrient loss, environmental sustainability, animal welfare and more. Whilst significant gaps persist in our understanding of fibre in non-ruminant animal production, there is substantial interest in optimizing the fibre fraction of feed to induce high value phenotypes such as improved welfare, live performance and to reduce the environmental footprint of animal production systems. In order to achieve these aspirational goals, it is important to tackle dietary fibre with the same level of scrutiny as is currently done for other critical nutrient classes such as protein, minerals and vitamins. The chemical, mechanical and nutritional role of fibre must be explored at the level of monomeric sugars, oligosaccharides and polysaccharides of varying molecular weight and decoration, and this must be in parallel to standardisation of analytical tools and definitions for speciation. To further complicate subject, exogenous carbohydrases recognise dietary fibre as a focal substrate and have varying capacity to generate lower molecular weight carbohydrates that interact differentially with the host and the enteric microbiome. This short review article will explore the interactive space between dietary fibre and exogenous carbohydrases and will include their nutritional and health effects with emphasis on functional development of the gut, microbiome modulation and host metabolism.

Effect of Different Feed Particle Size on Gastrointestinal Tract Morphology, Ileal Digesta Viscosity, and Blood Biochemical Parameters as Markers of Health Status in Broiler Chickens

The study is focused on how the physical structure of the feed affects the health status of broiler chickens. The aim of this study was to evaluate the influence of feed particle size in broiler diets on gastrointestinal tract morphology, digesta viscosity, and blood biochemical parameters. A total of 90 one-day-old male Ross 308 broiler chickens were randomly divided into three different experimental groups (with five replicates per pen), with 6 birds per cage. The first experimental group (Coarse) was fed with the coarsest particle size, with feed with a geometric mean diameter (GMD) of 1111.26 µm, the next group (Medium) was fed with a less coarse feed size of GMD 959.89 µm, and the last group (Fine) was fed a diet with a fine feed particle size of GMD 730.48 µm. The use of coarse feed particle size in the diet had a positive effect on the gizzard weight and small intestinal villi height and crypt depth, which increased the surface area intended for digesting nutrients. The use of finely ground particles in the feed increased the level of gamma-glutamyl transferase and at the same time, decreased the level of urea, which could indicate adverse changes in the liver.

Effect of Corn Grinding Methods and Particle Size on the Nutrient Digestibility of Chahua Chickens

This study investigates the effect of grinding methods, including roller mill, hammer mill, and two-stage grinding, on the particle size distribution of corn and the effect of corn particle size on the nutrient digestibility of native chickens in Southwest China. The roller mill, hammer mill, and a combination of the hammer mill and roller mill were used to obtain corn with various coarseness. Corn with different coarseness obtained using a combination of the hammer mill and roller mill was fed to Chahua chicken No. 2-type chickens (CHC2s). A total of 192 CHC2s in weeks 12 and 19 were randomly allocated to eight groups in triplicate. The results show that the geometric mean diameter (d_gw) and the geometric standard deviation (S_gw) were significantly (p < 0.05) affected by the grinding methods. The S_gw obtained when using a sieve of 2.0 mm in a hammer mill was lower (p < 0.05) than that obtained using a 4.5 mm sieve. Combining the roller mill and hammer mill increased the uniformity of the particle size when grinding coarse particles. For fine particles, the d_gw and S_gw obtained when using the hammer mill were significantly lower (p < 0.05) than those obtained when using the roller mill and two-stage grinding method. Reducing the particle size of the corn (<900 µm) significantly increased the dry matter, crude protein, amino acid digestibility, and apparent metabolizable energy in the chicken in weeks 12 and 19. Fine particles significantly increased the crude protein digestibility of the CHC2s at week 12, while there was no significant effect on the crude protein and amino acid digestibility in the CHC2s at week 19. In conclusion, different grinding methods can affect the particle size distribution. For a coarse particle size, combining the roller mill and hammer mill tends to produce a more uniform particle size. Finely ground corn (between 700 µm and 900 µm) improved the dry matter (DM), apparent metabolizable energy (AME), and crude protein (CP) digestibility of the CHC2s at week 12. An increased particle size did not impact the CP and amino acid (AA) digestibility of the CHC2s at week 19.

Effects of different processing techniques of broken rice on processing quality of pellet feed, nutrient digestibility, and gut microbiota of weaned piglets

The present study was conducted to assess the effect of different processing techniques of broken rice on processing quality of pellet feed, growth performance, nutrient digestibility, blood biochemical parameters, and fecal microbiota of weaned piglets. A total of 400 crossbred piglets (Duroc × Landrace × Yorkshire) with a mean initial body weight (BW) of 7.24 ± 0.52 kg were used in a 28-d experiment. Piglets were randomly distributed to one of 4 treatment and 10 replicate pens per treatment, with 10 piglets per pen. The dietary treatments were as follows: CON, corn as the main cereal type in the dietary; BR, 70% of the corn replaced by broken rice; ETBR, 70% of the corn replaced by extruded broken rice; EPBR, 70% of the corn replaced by expanded broken rice. Extruded broken rice and expanded broken rice supplementation significantly (P < 0.05) increased hardness, pellet durability index, crispness, and starch gelatinization degree. Extruded broken rice and expanded broken rice generated a higher (P < 0.05) average daily feed intake, increased (P < 0.05) average daily gain, decreased (P < 0.05) feed conversion ratio, and lowered (P < 0.05) the diarrhea rate. Piglets fed extruded broken rice displayed high apparent total tract digestibility levels of dry matter (P < 0.05), gross energy (P < 0.05), crude protein (P < 0.05), and organic matter (P < 0.05). In addition, extruded broken rice and expanded broken rice supplementation had increased Lactobacillus and Bifidobacterium levels in gut, whereas a lower abundance of the potential pathogens Clostridium_sensu_strictio_1 and Streptococcus was observed. Dietary supplementation of extruded broken rice and expanded broken rice failed to show significant effects on blood biochemical parameters. Combined, 70% corn substituted with broken rice failed to show significant effects. Collectively, extruded broken rice and expanded broken rice supplementation had positively enhanced the pellet quality, growth performance, nutrient digestibility, and gut microbiota of weaned piglets.

Influence of Expander Conditioning Prior to Pelleting on Pellet Quality, Broiler Digestibility and Performance at Constant Amino Acids Composition while Decreasing AMEN

Physical pellet quality and AMEN concentration are strongly related to each other in broiler feeding. A study was conducted to evaluate the relationship between dietary AMEN concentration and feed processing on pellet quality, nutrient digestibility, broiler performance, serum markers, and yield of commercial cuts. Six diets were formulated. The first diet had the recommended AMEN concentration, each further diet was calculated with 40 kcal/kg less, from 0 to −200 kcal/kg, resulting in six levels for each feed phase: starter (1−14 d), grower (15−28 d), and finisher (29−35 d). These diets were processed with and without expander conditioning prior to pelleting, using an average corn particle size of 1.6 mm, ground with a roller mill. A total of 1008 one-day-old male Ross 308 broiler chickens were placed in a 6 × 2 (6 energy levels and 2 conditionings) factorial trial with six boxes as replications, with three in each broiler performance trial period. Excreta were collected 2 days before the end of each feed phase for apparent total tract digestibility measurement. On day 36, four broilers from each replication (pen) were weighed and then euthanized for blood collection, following which the gastrointestinal organs were weighed, and the ileal and gizzard contents were collected. On day 37, all remaining broilers were slaughtered after fasting to measure commercial cuts and abdominal fat. The results show that the pellet durability index (PDI) was most affected by energy reducing and expander conditioning prior to pelleting, and it was better when diets had energy reduced by 40 to 200 kcal/kg (p > 0.001), as when expander conditioning was used. Digestibility of nutrients was slightly affected by treatments, as was the broiler performance; however, feed efficiency was improved in broiler-fed diets without AMEN reduction and when an expander was used, with p = 0.050 and p = 0.031, respectively. No effects were observed on the weight of gastrointestinal tract organs and serum markers, except for liver (p = 0.037) and α-amylase (p = 0.047). The lowest liver weight and lowest serum protein, cholesterol, triglyceride, gamma-glutamyl, and lipase concentrations were obtained when diets were formulated without energy reduction (Ross-0). There was no effect on commercial cuts relative to live weight at slaughter. The energy reduction was well reflected in the proportion of abdominal fat, which decreased when AMEN was reduced (p = 0.001). The present study shows it is possible to use diets with up to 200 kcal/kg reduction in AMEN without losses in performance, and the use of expander conditioning prior to pelleting promotes higher pellet quality and broiler feed efficiency.

Towards Large Particle Size in Compound Feed: Using Expander Conditioning Prior to Pelleting Improves Pellet Quality and Growth Performance of Broilers

During the processing of compound feed for broilers, several changes occur that affect the physical and probably the nutritional properties of pellets, influencing animal performance. The effects of mill type, particle size (PS) and expander conditioning prior to pelleting (E + P) were combined to generate pellets. A 2 × 3 × 2 factorial arrangement was designed with two mill types (a hammer mill (HM) or roller mill (RM)), three PSs (0.8, 1.2 or 1.6 mm) and two E + Ps (with or without expander processing prior to pelleting), with six replications of 12 unsexed Ross 308 broilers each. All the processing lines reduced the PS from mash to finished pellets via secondary grinding, by 2.35 times on average. However, RM grinding required less electric power (p < 0.001). The intended PS (0.8, 1.2 or 1.6 mm) did not affect this energy consumption. E + P and the PS interacted for the pellet durability index (PDI) (p = 0.006). The worst PDI in the pellets was observed when a PS of 1.6 mm without E + P was used. Only E + P positively affected starch (p < 0.001) and amino acids’ ileal apparent digestibility (p < 0.01). Organic matter (OM) (p = 0.02) and fat (p < 0.001) digestibility, as well as AMEN (p = 0.005) content, were influenced by the PS (main effect), whereas E + P and mill type interacted with these values (p < 0.005). Lower OM digestibility and AMEN content were observed when RM without E + P was used (p = 0.001). The feed conversion ratio (FCR) was enhanced and feed intake (FI) was improved with E + P. The combination of the RM mill, a 1.6 mm mean PS, and E + P improved FCR (three-way interaction, p = 0.019)), showing that for a higher PS, E + P is necessary for animal performance. Carcass yield was, on average, 80.1%. No effects on commercial cuts (breast, legs and wings) were observed. In contrast, abdominal fat was affected by mill type * PS (p = 0.012) and E + P * PS (p = 0.048) in a two-way interaction. The highest abdominal fat indicated an imbalance in the amino acid (AA)-to-AMEN ratio. Coarse PS promoted heavier gizzards (p = 0.02) but E + P tended to reduce them (p = 0.057). The processing steps improved pellet quality and feed efficiency associated with RM, coarse PS and E + P, highlighting the positive effects of E + P on abdominal fat and AMEN content, which should be adjusted to AA or reduced at formulation. However, these results are for an experimental processing plant and may not necessarily apply to larger plants, so the use of these data and methods should be considered as guidelines for replication at production sites.

Physicochemical Changes of Heat-Treated Corn Grain Used in Ruminant Nutrition

Cereal grain is processed using different combinations of heat, moisture, time, and mechanical action in order to improve its digestibility. The objective of the present research was to quantitatively represent the physicochemical properties of raw and processed starch using an in vitro methodology, as well as to describe the changes that occurred after heat treatment, such as pelleting, steam flaking, micronization, and extrusion of corn. Based on the obtained results, pelleting, steam flaking, and micronization can be considered as mild heat treatment methods, whereas extrusion proved to be a severe heat treatment method. Analysis of functional and pasting properties implied a possible interaction between the degraded components in the steam-flaked sample, as well as in the micronized sample, through to a lesser extent. Additionally, the occurrence of dextrins was noted after extrusion. The obtained results indicate the existence of significant differences in the physicochemical properties of corn starch depending on the heat treatment applied, which could possibly affect rumen starch degradation traits.

Transcriptome-wide analysis reveals gluten-induced suppression of small intestine development in young chickens

Wheat gluten is an increasingly common ingredient in poultry diets but its impact on the small intestine in chicken is not fully understood. This study aimed to identify effects of high-gluten diets on chicken small intestines and the variation of their associated transcriptional responses by age. A total of 120 broilers (Ross Strain) were used to perform two animal experiments consisting of two gluten inclusion levels (0% or 25%) by bird’s age (1 week or 4 weeks). Transcriptomics and histochemical techniques were employed to study the effect of gluten on their duodenal mucosa using randomly selected 12 broilers (3 chicks per group). A reduction in feed intake and body weight gain was found in the broilers fed a high-gluten containing diet at both ages. Histochemical photomicrographs showed a reduced villus height to crypt depth ratio in the duodenum of gluten-fed broilers at 1 week. We found mainly a significant effect on the gene expression of duodenal mucosa in gluten-fed broilers at 1 week (289 differentially expressed genes [DEGs]). Pathway analyses revealed that the significant DEGs were mainly involved in ribosome, oxidative phosphorylation, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. These pathways are involved in ribosome protein biogenesis, oxidative phosphorylation and fatty acid metabolism, respectively. Our results suggest a pattern of differential gene expression in these pathways that can be linked to chronic inflammation, suppression of cell proliferation, cell cycle arrest and apoptosis. And via such a mode of action, high-gluten inclusion levels in poultry diets could lead to the observed retardation of villi development in the duodenal mucosa of young broiler chicken.

Influence of barley inclusion method and protease supplementation on growth performance, nutrient utilisation, and gastrointestinal tract development in broiler starters

The influence of the method of barley inclusion (fine, coarse and whole barley) in a wheat-based diet and protease supplementation (0 and 0.20 g/kg) on growth performance, nutrient utilisation and gastrointestinal tract development of broilers (d 1 to 21) was evaluated in a 3 × 2 factorial arrangement. Whole barley (WB) grains were ground in a hammer mill to pass through the screen sizes of 2.5 and 8.0 mm to achieve fine (FB) and coarse (CB) barley particle sizes, respectively. A total of 288, one-day-old male broilers were allotted to 36 cages (6 cages/treatment; 8 birds/cage). There was no significant (P > 0.05) interaction between barley inclusion method and protease for any growth performance or nutrient utilisation parameters. Birds fed diets containing CB and WB showed higher (P < 0.05) weight gain, and digestibility of dry matter, nitrogen, calcium, gross energy, and ileal digestible energy compared to those fed FB diets. Compared to the birds fed FB diets, feed per gain was lower (P < 0.05) in birds fed diets made of WB. Fat digestibility of the birds fed CB was higher (P < 0.05) than those fed FB and WB birds. Compared to FB and CB diets, inclusion of WB resulted in heavier (P < 0.05) gizzards but reduced (P < 0.05) gizzard pH. Supplemental protease, however, had no effects (P > 0.05) on growth performance and nutrient utilisation, most likely due to the well balanced digestible amino acids and high inherent digestibility of protein in the basal diet, and/or the presence of exogenous carbohydrase and phytase. In conclusion, the present results showed that the inclusion of coarsely ground and whole barley in a wheat-based diet can enhance nutrient and energy utilisation and is beneficial to the growth performance of young broilers.

Textural, Color and Sensory Features of Spelt Wholegrain Snack Enriched with Betaine

The influence of different extrusion parameters, including screw speed (250–750 rpm), feed rate (15–25 kg/h) and feed moisture content (15–25%), on the textural and color properties of spelt wholegrain snack products produced on a co-rotating twin-screw extruder with added betaine was investigated. In order to determine the relative influence of input variables in the artificial neural network (ANN) model, Yoon’s interpretation method was used, and it was concluded that feed moisture content has the greatest influence on L* values, while screw speed has the greatest influence on a* and b* values. The softest samples were obtained at the lowest moisture content. Sensory analysis was carried out on selected samples, and it showed that betaine addition did not intensify the bitter taste. The sample with the largest expansion exhibited the lowest hardness and chewiness before and after immersion in milk, and this sample is the most suitable for enrichment with betaine.

Effect of pelleting on nutrients and energy digestibility in growing pigs fed corn-soybean meal-based diet or diet containing corn distillers dried grains with solubles (cDDGS), wheat middlings, and bakery meal

This study was conducted to determine the effect of pelleting and diet type on the apparent ileal (AID) and total tract digestibility (ATTD) of nutrients and energy in growing pigs. Six pigs were cannulated at the ileum and were assigned to treatments following a crossover design. One diet was a control diet based on corn and soybean meal (CT). Part of it was replaced by corn distillers dried grains with solubles (cDDGS), wheat middlings, and bakery meal in the second diet (ByP). Diets were in mash (CT-MH and ByP-MH) or pelleted (CT-PT and ByP-PT) form. Results showed that pelleting increased digestibility in all diets with a distinct effect on the CT diet (interaction diet × pelleting, P < 0.05). Pelleting improved the AID of dry matter, crude protein, and energy by 17%, 27%, and 17% in the CT diet and by 10%, 9%, and 17% in the ByP diet (P < 0.01). The AID of amino acids followed the effect observed on crude protein (P < 0.01). Pelleting increased AID of total non-starch polysaccharides for the CT diet by 63% and 42% for the ByP diet (P < 0.01). The pelleting conditions improved the degradability of the compounds in the diets during digestion in pigs.

Lignocellulose as an insoluble fiber source in poultry nutrition: a review

Extensive research in recent years into the use of various fiber sources in poultry nutrition has led to the perception that dietary fiber is more than a simple diet diluent. Several studies showed that the feeding of insoluble fiber sources such as oat hulls, sunflower hulls or wood shavings may affect digestive physiology and function improving chickens health and growth performance. In this context, the effect of lignocellulose as an insoluble dietary fiber source is increasingly being investigated. Lignocellulose is a component of plant cell walls and consists mainly of the insoluble carbohydrate polymers cellulose and hemicelluloses as well as the phenolic polymer lignin. Lignocellulose is chemically and physicochemically different from other insoluble fiber sources and thus possibly has different effects on poultry compared to traditional fiber sources. Several studies investigated the effect of dietary lignocellulose on growth performance, nutrient digestibility, gastrointestinal tract development and intestinal microbiota in broilers and laying hens. Studies differed in terms of feed formulation and lignocellulose inclusion level as well as products of different suppliers were used. The results obtained are inconsistent; beneficial, indifferent or detrimental effects of feeding lignocellulose were observed, so that a final assessment of lignocellulose as a “novel” insoluble fiber source is difficult. This review article summarizes the results of studies in connection with the feeding of lignocellulose to poultry, compares them with those that have used other insoluble fiber sources and illuminates the possible mechanisms of action.

Macro- and microstructures of the digestive tract in the Eurasian collared dove, Streptopelia decaocto (Frivaldszky 1838): Adaptive interplay between structure and dietary niche

We describe the functional morphology of the digestive tract of the Eurasian collared dove, Streptopelia decaocto using anatomical, morphometric, histological, histochemical, and ultrastructure techniques, and relate our findings to the species' dietary niche. Our results revealed that the esophagus is displaced on both sides of the neck and has highly folded tunica mucosa, which confer greater elasticity for efficient swallowing and passage of food to the crop. The proventriculus is delicate and its mucosal layer contains polymorphic glands with dense profound and superficial secretory units that open to the luminal surface by gastric pores. The ventriculus is biconvex and lined with a keratinized koilin membrane. The tubular glands within the mucosal lining include the isthmus, the neck, and the basal segment that comprise chief and basal cells with prominent nuclei. At the cuticle-mucosal interface, pyramidal vertical rodlets of the cuticle are secreted and superficially covered by a thin film of a horizontal matrix. The mucosa of the ileum form pyramidal villi that are oriented perpendicularly to the central lumen. Enterocytes infiltrated with goblet cells make up the epithelial lining of the villi. There are subtle differences in the thicknesses of corresponding tunics together with histochemical reactions of alcian blue (AB) and Masson-Goldner trichrome (MT) for their microstructures. Overall, our findings reveal remarkable convergence of both macro-and microstructures in S. decaocto to other granivorous species, and offer further evidence of the close association between functional morphology and feeding style relative to food swallowing, digestion, and absorption.

Effects of ground, steam-flaked, and super-conditioned corn grain on production performance and total-tract digestibility in dairy cows

This study aimed to evaluate the effects of feeding ground, steam-flaked, or super-conditioned corn on production performance, rumen fermentation, nutrient digestibility, and milk fatty acid (FA) profile of lactating dairy cows. Twenty-four lactating Holstein cows (130 ± 12 d in milk) in a completely randomized block design experiment were assigned to 1 of 3 treatments that contained 31% of one of the following corn types: (1) ground corn; (2) steam-flaked corn; and (3) super-conditioned corn. Actual milk yield was greater in the super-conditioned corn diet than in the steam-flaked and ground corn diets. Dry matter intake, 3.5% fat-corrected milk and energy-corrected milk remained unaffected by treatments; however, milk fat concentration decreased in the super-conditioned corn diet compared with the ground and steam-flaked corn diets. The molar proportion of ruminal acetate decreased in the super-conditioned corn diet compared with the ground and steam-flaked corn diets, whereas the molar proportion of propionate spiked in the super-conditioned corn diet. Ruminal pH dropped in cows fed super-conditioned corn compared with the other 2 diets. A similar pattern was observed for ruminal NH₃-N and acetate-to-propionate ratio. Total-tract starch digestibility increased the most in the super-conditioned corn diet followed by the steam-flaked and ground corn diets (96.8, 95.1, and 92.5%, respectively). The neutral detergent fiber digestibility declined in cows fed the super-conditioned corn diet as opposed to other diets (~3.9%). The concentrations of 16:0 and mixed-FA in milk fat dropped in the super-conditioned corn-based diet compared with the ground corn diet. Milk trans-10 18:1 FA increased, whereas trans-11 18:1 FA decreased in cows fed the super-conditioned diet. We concluded that super-conditioned corn has the potential to increase milk yield and starch digestibility in lactating dairy cows; however, reduced milk fat output caused by altering ruminal pH and ruminal FA biohydrogenation pathways may not be desirable in certain markets. Future research is warranted to investigate how super-conditioned corn affects feed efficiency.

Effect of the Pellet and Mash Feed Forms on the Productive Performance, Egg Quality, Nutrient Metabolism, and Intestinal Morphology of Two Laying Hen Breeds

Simple Summary

Although there is an established understanding of the nutritional requirements for poultry production, the evaluation of the feed form for chickens still needs to be further examined. It is generally believed that a pellet diet has a positive effect on chicken growth, but there are some studies that have reported no difference between pellet and mash on chicken’s performance. The present study indicated that pellet diets improved the production performance and nutrition metabolism through positive changes in the laying rate, feed intake, egg albumen quality and apparent digestibility of laying hens.

Abstract

One of the most important factors that determine feed utilization by chickens is the feed form. Although it is generally believed that pellet diets have a positive effect on chicken growth, there are some studies that have indicated no difference between pellet and mash on chickens performance. This study was conducted to assess the effects of feed form on production performance, egg quality, nutrient metabolism and intestinal morphology in two breed laying hens. Two hundred and sixteen 25-week-old Hy-Line brown (n = 108) and Hy-Line grey (n = 108) hens were selected. Each breed was randomly allocated into two treatments with 6 replications (9 birds in each replication), which were fed mash and pellet diets, respectively. Production performances were recorded daily and egg quality traits were measured every two weeks. At 42 weeks of age, one bird per replication from each experimental group was selected for metabolism determination and intestine morphology observation. Compared with mash diets, pellet diets improved laying rate (p < 0.05), ADFI (average daily feed intake, p < 0.05), egg weight, shell strength, yolk proportion and Haugh unit (p < 0.05) in both breeds and reduced the FCR (feed conversion ratio, p < 0.05) in Hy-Line grey. The apparent digestibility of DM% (dry matter) and CP% (crude protein) were significantly higher (p < 0.05) in both breed laying hens fed pellet than those fed mash. The apparent digestibility of P% (phosphorus) and Ca% (calcium) was higher in Hy-Line grey fed pellet and was higher in Hy-Line brown fed mash. Compared to mash diets, pellet diets increased the VH (villus height), CD (crypt depth) and VCR (ratio of villus height to crypt depth) of the small intestine of Hy-Line grey, and increased the VH and CD of duodenum and ileum of Hy-Line brown. Overall, pellet diets improved production performance and nutrition metabolism through positive changes in the laying rate, feed intake, egg albumen quality and apparent digestibility of laying hens. The current findings provided support for the advantages of feeding pellets during the peak egg laying period for the two popular laying hen strains, Hy-Line brown and Hy-Line grey.

Using Nutritional Strategies to Shape the Gastro-Intestinal Tracts of Suckling and Weaned Piglets

This is a comprehensive review on the use of nutritional strategies to shape the functioning of the gastro-intestinal tract in suckling and weaned piglets. The progressive development of a piglet's gut and the associated microbiota and immune system offers a unique window of opportunity for supporting gut health through dietary modulation. This is particularly relevant for large litters, for which sow colostrum and milk are insufficient. The authors have therefore proposed the use of supplemental milk and creep feed with a dual purpose. In addition to providing nutrients to piglets, supplemental milk can also serve as a gut modulator in early life by incorporating functional ingredients with potential long-term benefits. To prepare piglets for weaning, it is important to stimulate the intake of solid feed before weaning, in addition to stimulating the number of piglets eating. The use of functional ingredients in creep feed and a transition diet around the time of weaning helps to habituate piglets to solid feed in general, while also preparing the gut for the digestion and fermentation of specific ingredients. In the first days after weaning (i.e., the acute phase), it is important to maintain high levels of feed intake and focus on nutritional strategies that support good gastric (barrier) function and that avoid overloading the impaired digestion and fermentation capacity of the piglets. In the subsequent maturation phase, the ratio of lysine to energy can be increased gradually in order to stimulate piglet growth. This is because the digestive and fermentation capacity of the piglets is more mature at this stage, thus allowing the inclusion of more fermentable fibres. Taken together, the nutritional strategies addressed in this review provide a structured approach to preparing piglets for success during weaning and the period that follows. The implementation of this approach and the insights to be developed through future research can help to achieve some of the most important goals in pig production: reducing piglet mortality, morbidity and antimicrobial use.

Standardized ileal amino acid digestibility of protein sources for broiler chickens is influenced by the feed form

The aim of present study was to determine the influence of the feed form (FF) on standardized ileal digestibility (SID) of nitrogen (N) and amino acids (AA) in 3 protein sources (PS) for broiler chickens. Six diets were tested in a 3 × 2 factorial arrangement of treatments involving 3 PS (meat and bone meal [MBM], soybean meal [SBM], and canola meal [CM]) in mash and pelleted forms. The basal endogenous N and AA losses were determined by offering a N-free diet in the mash form. From day 1 to 18, the birds were offered a broiler starter diet. The diets and the N-free diet were randomly assigned to 6 replicate cages (8 birds per cage) and fed from day 19 to 23. The ileal digesta were collected on day 23. The SID of N was higher (P < 0.05) in SBM followed by MBM and CM. The average SID of AA in SBM and MBM were similar (P > 0.05), and greater (P < 0.05) than that in CM. The FF had no influence (P > 0.05) on the SID of indispensable AA, the only exception being His, which was reduced (P < 0.05) by pelleting. Pelleting, however, resulted in reduction (P < 0.001) in the SID of all dispensable AA and average of AA. The AA most affected by pelleting was Cys, with a 15.4% decrease in the SID. The standardized ileal digestible contents of protein and the average of indispensable AA and dispensable AA were higher in MBM than in SBM, with CM being the lowest. Pelleting decreased (P < 0.05) the digestible protein and total digestible AA contents. These findings reveal that the FF has a substantial impact on AA digestibility estimates of feed ingredients and it must be considered in AA digestibility assays of ingredients with high protein and AA contents.

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.

Corn drying temperature, particle size, and amylase supplementation influence growth performance, digestive tract development, and nutrient utilization of broilers

Broiler live performance may be influenced by postharvest corn drying temperature, and results could depend on particle size after grinding. The supplementation with an exogenous amylase may improve performance parameters, but responses to enzymes are also affected by particle size. Two parallel experiments were conducted to evaluate the effects of hard-kernel corn dried at 2 temperatures (35°C and 120°C), ground at 2 particle sizes (coarse or fine), and 3 supplementation levels (0, 133, and 266 g ton-1) of an exogenous amylase on live performance, gastrointestinal organ development, energy utilization, and nutrient digestibility. Twelve dietary treatments resulting from a 2 × 2 × 3 factorial arrangement of drying temperature, particle size, and amylase supplementation were evaluated in both experiments. A total of 1,920 day-old male chicks were randomly allocated to 96 floor pens, while 480 chicks were distributed among 4 battery brooder units. Ileal and fecal samples were collected to determine energy utilization and nutrient digestibility using titanium dioxide as inert marker. At 42 D, organs were collected, and relative weight or length was determined. Data were analyzed using a three-way ANOVA in a randomized complete block design. Feeding fine corn-based diets showed improvements on live performance for both studies. At 40 D, supplementing 266 g ton-1 of amylase improved feed conversion ratio (P < 0.05) by 1 point compared to chickens that consumed nonsupplemented diets and feed with amylase at 133 g ton-1. Broilers fed coarse corn-based diets had heavier gizzard (P < 0.001) and liver (P < 0.05) than chickens that consumed fine corn-based diets. In addition, starch digestibility was improved by amylase (P < 0.05) at 133 g ton-1 and by feeding coarse corn-based diets (P = 0.06). For chicks raised in cages (16 D), AMEn was increased (P < 0.01) by amylase supplementation regardless of its inclusion level. In conclusion, drying temperature and particle size interactions influenced broiler live performance, gastrointestinal organ development, nutrient digestibility, and energy utilization, and these parameters were improved by supplementing amylase.

Intestinal starch and energy digestibility in broiler chickens fed diets supplemented with α-amylase

Dietary starch is the major energy source for broiler chickens; therefore, relevant information on its intestinal utilization is important. The present study was designed to evaluate intestinal starch and energy digestibility of broiler chickens fed diets supplemented with α-amylase. A total of 240 day-0 male broiler chicks were randomly assigned to 3 nutritionally adequate corn-soybean-based experimental diets comprising 3 levels of α-amylase supplementation (0, 80, or 160 KNU/kg diet). Each treatment comprised 8 replicate cages of 10 birds each. At day 21 after hatching, digesta was collected from 4 intestinal sites: the anterior jejunum (AJ), posterior jejunum (PJ), anterior ileum (AI), and posterior ileum. Increasing α-amylase supplementation linearly improved (P < 0.01) overall BW gain and feed efficiency of the birds. There were linear and quadratic (P < 0.01) responses of increasing α-amylase supplementation on starch and energy digestibility at the PJ and AI. The total tract digestibility of starch increased (P < 0.05) with increasing α-amylase supplementation. Starch disappearance and digestible energy (kcal/kg) linearly increased (P < 0.01) with digesta flow from the AJ to PJ as dietary α-amylase supplementation increased. There were linear (P < 0.01) and quadratic (P < 0.05) effects of increasing α-amylase supplementation on the villus height in the jejunum. The viscosity of the jejunal digesta decreased (P < 0.05) with increasing dietary α-amylase supplementation. The results from this study showed the efficacy of exogenous amylase in improving growth performance and starch and energy digestibility in broiler chickens. Furthermore, the digestibility of starch and energy and the impact of the exogenous amylase were higher at the PJ than other intestinal sites.

Influence of Particle Size and Xylanase in Corn-Soybean Pelleted Diets on Performance, Nutrient Utilization, Microbiota and Short-Chain Fatty Acid Production in Young Broilers

The objective of this study was to investigate the effects of particle size and xylanase supplementation in corn-based pellet diets on the performance and digestive traits in young broilers. A total of 512 male Ross 308 broilers were used in a 21-day study. The treatments were designed in a 4 × 2 factorial arrangement with four levels of geometric mean diameter (Dgw) of corn (540, 660, 1390, and 1700 µm), and two levels of xylanase (0 or 16,000 BXU/kg diet). Feeding coarse corn diets (1390 and 1700 µm Dgw) and xylanase supplementation showed an inferior coefficient of variation of body weight. Higher gizzard weight, microbiome alpha-diversity, and clustered separately beta-diversity (p < 0.05) were observed in birds fed coarse diets. The addition of xylanase promoted changes in relative bacteria abundance, increasing Lachnospiraceae, Defluviitaleaceae, Bacteroidaceae, Bacillaceae, Eggerthellaceae, and Streptococcaceae families in the 1700 µm group, and Christensenellaceae and Lachnospiraceae families in the 540 µm Dgw group. In conclusion, xylanase supplementation and particle size of corn interact in the intestinal environment, showing changes in microbial composition. Coarse diets and xylanase supplementation showed improved body weight homogeneity, which might be related to a better gut development and microbiota modulation.

Effects of conditioner retention time during pelleting of starter feed on nutrient digestibility, ruminal fermentation, blood metabolites, and performance of Holstein female dairy calves

This study evaluated the effects of conditioner retention time during the pelleting process of starter feed on intake, nutrient digestibility, ruminal fermentation, blood metabolites, and growth performance of dairy calves. A total of 30 Holstein female dairy calves [40 ± 1.93 kg of body weight (BW)] were randomly assigned to 1 of 3 treatments: (1) pelleted starter conditioned for 0 min (CON), (2) pelleted starter conditioned for 2 min, and (3) pelleted starter conditioned for 4 min. Three pelleted starter feeds had similar nutritional composition, and the starters were blended with 3% chopped wheat straw and fed to individually housed calves from d 3 to 70 of age. All calves were fed 4 L/d of pasteurized whole milk twice daily at 0800 and 1600 h from d 3 to 50 of calf age, followed by 2 L/d of morning feeding from 51 to 56 d of age. All calves were weaned on d 56 of age and remained in the study until d 70 of age. With the increase of conditioner retention time during pellet processing for 0, 2, and 4 min, the gelatinized starch content of pelleted starter feed linearly increased from 14, 30, and 45%, respectively. Additionally, the pellet durability and hardness also linearly increased with increasing conditioner retention time during pelleting. Feeding pelleted feed prepared using different conditioner retention time did not affect feed dry matter intake, metabolizable energy intake, weaning BW, final BW, or feed efficiency during the study. We observed no differences in the total-tract apparent digestibility of organic matter, neutral detergent fiber, and crude protein around weaning (d 49 to 56 of age) and after weaning (d 63 to 70 of calf cage); however, the digestibility of dry matter and starch after weaning was increased with increasing conditioner retention time during pelleting of starter feed. No difference was found in overall average daily gain (ADG) or growth rates of hip height, withers height, and heart girth. Ruminal volatile fatty acid profile was not affected by pelleting under different conditioner retention times. The ruminal ammonia concentration tended to be lower for calves fed the 4-min diet compared with those fed the CON diet during the postweaning period. The postweaning (d 57-70 of age) ADG was greater for calves fed the 4-min diet compared with those fed the CON diet. In conclusion, the conditioning time during the pelleting process of starter feed increased the gelatinization of starch, durability, and hardness of the pellets but did not influence feed intake, feed efficiency, and skeletal growth during the first 70 d of age. Increasing conditioning time during the pelleting process improved postweaning ADG; however, the final BW of calves was similar among treatments.

Can the digestibility of corn distillers dried grains with solubles fed to pigs at two stages of growth be enhanced through management of particle size using a hammermill or a roller mill?

The objective of this study was to determine the impact of reducing the mean particle size (PS) of corn distillers dried grains with solubles (DDGS) with a hammermill (HM) or with a roller mill (RM) on the apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), N, acid hydrolyzed ether extract (AEE), and fiber components in growing and finishing pigs. Twenty-four growing barrows were housed in individual pens and were randomly assigned to a 3 × 2 factorial design (n = 8): three grinding methods [either corn DDGS ground with an HM to a PS of 450 μm; corn DDGS ground with an RM to a PS of 450 μm; and corn DDGS with a PS of 670 μm (not further ground)] and two body weight (BW) periods (growing pigs with an average initial BW of 54.7 ± 0.9 kg, and finishing pigs with an average initial BW of 107.8 ± 1.5 kg BW). Fecal samples were collected for each BW period in the last 3 d of an 11-d feeding period. Titanium dioxide was used as an indigestible marker. Digestibility data were analyzed using the MIXED procedure of SAS. Results showed that finishing pigs tended to have better ATTD of DM than growing pigs (P = 0.09) and had increased ATTD of GE and N than growing pigs (P = 0.03 and P < 0.01, respectively). On the other hand, growing pigs had better ATTD of AEE than finishing pigs (P = 0.01). Pig BW period did not affect the ATTD of neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose. Reducing the mean PS of corn DDGS with either HM or RM (from 670 to 450 µm) improved the ATTD of DM and GE (P < 0.01 and P < 0.01), tended to improve the ATTD of N (P = 0.08), and improved the ATTD of AEE (P < 0.01). No effect of reducing PS was observed for the ATTD of NDF, ADF, or hemicellulose. There were no differences between HM and RM in any of the ATTD variables tested. In conclusion, reducing PS of corn DDGS from 670 to 450 μm either with an HM or with an RM improved the digestibility of DM, GE, and AEE and modestly improved the digestibility of N in growing and finishing pigs. However, reducing the PS of corn DDGS did not affect the digestibility of fiber components.

The interactive influence of barley particle size and enzyme supplementation on growth performance, nutrient utilization, and intestinal morphometry of broiler starters

The influence of barley particle size and enzyme supplementation on performance, nutrient and energy utilization, and intestinal morphometry of broiler starters (day 1–21) fed pelleted barley-based diets was evaluated. Two barley particle sizes (fine and coarse) and 4 enzyme treatments (nonsupplemented [control], carbohydrase [0.15 g/kg of feed; Carb], phytase [0.10 g/kg; Phy] and combination of carbohydrase and phytase [0.15 and 0.10 g/kg, respectively; Carb + Phy]) were evaluated in a 2 × 4 factorial arrangement. Fine and coarse barley particles were achieved by grinding whole barley in a hammer mill to pass through 2.0 and 8.0 mm screens, respectively. A total of 384, 1-day-old male broilers (8 birds/cage; 6 cages/treatment) were used. Supplemental enzymes tended (P = 0.056) to increase the weight gain of birds with a synergetic effect from Carb + Phy. The response of feed intake to supplemental enzymes interacted (P < 0.05) with barley particle size, as Phy increased feed intake only in fine barley diets. Both coarse particles and supplemental Carb, either individually or in combination with Phy, reduced feed per gain (P < 0.001). Digestibility of DM, nitrogen, and fat was greater in birds fed coarse barley diets (P < 0.05). Dry matter, starch, fat, and phosphorus digestibility values were improved by supplemental enzymes (P < 0.05). Coarse barley (P < 0.05) and Carb (P < 0.001), either individually or in combination, increased the AMEn. Coarse barley reduced the gizzard pH (P < 0.001). Birds fed diets with supplemental enzymes had shorter jejunum (P < 0.05). Neither the barley particle size nor supplemental enzymes (P > 0.05) affected the jejunal digesta viscosity. In summary, feeding coarse barley particles and supplemental Carb improved the feed efficiency and nutrient and energy utilization. The effects of barley particle size on measured parameters suggest that the particle size effect was preserved even after pelleting. The combination of Carb and Phy tended to improve the weight gain but caused no further improvements in nutrient utilization.

Thermal processing of corn and physical form of broiler diets

This study aimed to assess the effect of preprocessing of corn and of physical form of diets on growth performance, carcass yield, and nutrient digestibility in broilers and also the influence of corn processing on pellet quality. A total of 1,080 male Cobb chicks from 1 to 35 D were evaluated. Birds were distributed according to a completely randomized design in a 3 × 2 factorial arrangement, with 3 types of corn processing (unprocessed, pelleted, or expanded), and 2 diet physical forms (mash or pelleted), totaling 6 treatments and 9 replicates with 20 birds. The data were submitted to ANOVA, and means were compared by Tukey's test (P < 0.05). There was no interaction between the physical form and preprocessing of corn for any of the studied variables (P > 0.05). The use of expanded corn in the diets before pelleting resulted in higher pellet durability index and lower amount of fines (P < 0.05) when compared with unprocessed corn. Broilers fed pelleted diets had higher feed intake (FI) and weight gain (WG; P < 0.001), higher amounts of abdominal fat (P < 0.05), and lower ileal digestible energy (IDE, P = 0.05) than those fed mash. There was no effect of the feed form on nutrient digestibility (P > 0.05). Broilers fed diets with unprocessed corn had higher FI when compared to those fed diets with expanded or pelleted corn (P < 0.001). The use of pelleted corn resulted in lower WG than the other processing methods (P < 0.01). The corn expansion process improved feed conversion ratio and adjusted feed conversion ratio (P < 0.001). Inclusion of expanded corn improved the coefficient of apparent ileal digestibility of DM, CP, starch, and IDE (P < 0.05) in comparison with unprocessed corn. It is concluded that pelleted diets improve broiler performance. The corn expansion can be used to improve physical quality of the diets and broilers growth performance and nutrient digestibility.

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.

Impact of corn particle size on nutrient digestibility varies depending on bird type

The interaction between bird type (broilers and layers) and corn particle size (fine, medium, and coarse) on the coefficient of apparent ileal digestibility (CAID) of DM, nitrogen (N), starch, fat, gross energy (GE), calcium (Ca) and phosphorus (P), and AMEn was investigated in a 2 by 3 factorial study of 6 dietary treatments. Whole corn was ground in a hammer mill to pass through screen sizes of 2.0, 5.0, and 8.0 mm for fine, medium, and coarse grades, respectively. A corn-soybean meal diet, mixed using the same batch of ingredients, was fed to both bird types. Titanium dioxide was included in all diets for digestibility measurements. 35-day-old Ross 308 male broilers and 59-wk-old Hy-Line Brown layers were used in this study. For each bird type, 108 birds of uniform body weights were accommodated in 18 replicates (6 replicates per particle size and 6 birds per replicate). The treatment diets were offered ad libitum for 7 d prior to the collection of ileal digesta. A bird type by particle size interaction was observed (P < 0.001) for the CAID of DM, starch and GE. In broilers, CAID of DM, starch and GE was unaffected by particle size, whilst in layers, increasing the corn particle size to medium and coarse resulted in a greater (P < 0.05) CAID for DM, starch and GE compared to fine particles. The CAID of N and fat was greater (P < 0.05) in broilers than layers and the opposite was observed (P < 0.05) for Ca and P. Regardless of bird type, coarse and medium-ground corn resulted in a greater (P < 0.05) Ca digestibility compared to finely-ground corn. Overall, broilers had a greater digestibility of nutrients than layers, except for Ca and P. Feeding medium and coarse corn particles benefited the CAID of DM, starch and GE in layers, suggesting that digestive system in these birds is probably more sensitive to feed particle size than broilers.

Effect of pelleting and different feeding programs on growth performance, carcass yield, and nutrient digestibility in broiler chickens

This experiment was conducted to study the effect of different feeding programs and pelleting on performance, nutrient digestibility, ileal digestible energy (IDE); and carcass yield of broilers from 21 to 35 d of age. In total, 768 male broilers were distributed according to a completely randomized design with 6 treatments and 8 replicates of 16 birds each. The treatments were mash and pelleted diets provided ad libitum, or pelleted and supplied at the same rate (100%) or restricted at 95, 90, and 85% (P100, P95, P90, and P85) of the amount consumed by the birds fed mash diet ad libitum. When supplied ad libitum, the pelleted diet had the highest feed intake and weight gain (WG), better feed conversion ratio (FCR), better feed conversion adjusted for 2.3 kg (AdjFCR, P < 0.001) and caloric conversion (P < 0.001); and higher amount of abdominal fat (P < 0.001) when compared to the control (mash ad libitum). However, there were no effects on nutrient digestibility (P > 0.05). When the pelleted feed was provided in the same amount as in the control group, there were no differences in any of the evaluated parameters (P > 0.05). Limiting pelleted diet to 95, 90, and 85% of free choice mash diet resulted in lower WG (P < 0.001). P90 and P95 treatments resulted in higher dry matter and crude protein digestibility and IDE in relation to the others (P < 0.001). Carcass yield was reduced (P < 0.05) in the birds fed P85 diet. The regression analysis between P100, P95, P90, and P85 showed a linear reduction in WG when restriction was increased (P < 0.01); however, there was a linear increase in the nutrient digestibility (P < 0.001). It is concluded that pelleting improves broiler performance, but these results depend on feed intake. The higher intake provided by pelleting can increase the amount of abdominal fat. Feed intake reduction can result in lower performance and lower carcass and cuts yield in broilers.

Evaluation of the nutritive value of legume alternatives to soybean meal for broiler chickens

Five experiments were conducted to investigate the nutritional value of various legumes and a faba beans processing co-product for broilers. In Expt. 1 and 3, metabolizable energy (AME) content was evaluated for 2 batches of bean starch concentrate (BSC) that differed in physical and chemical characteristics. Standardized ileal amino acid digestibility (SIAAD) was determined for BSC in Expt. 2, and for corn, soybean meal (SBM), organic and conventional faba beans, and quinoa (Expt. 4). The growth performance response of broiler chickens to partial replacement of wheat and SBM with various legumes was investigated in Expt. 5. The AME of the BSC assayed in Expt. 1 was lower (P < 0.01) than that of the BSC assayed in Expt. 3. The SIAAD was generally high for BSC in Expt. 2 although the content and digestibility of sulfur amino acids were low. In Expt. 4, there was no difference in SIAAD of Arg, Phe, Asp, and Gly among the different feedstuffs assayed. SIAAD was largely similar for both conventional and organic faba bean. The SIAADs of Met, Thr, Ser, and Tyr were lower (P < 0.05) for quinoa compared with SBM or corn. In Expt. 5, FCR was greater (P < 0.05) for broiler chickens receiving faba beans+barley mix or lupins compared with the wheat-SBM control diet. Amino acid digestibility was greater (P < 0.01) for the diets containing lupins compared with the other diets except for Lys, Met, Thr, Ala, Asp, and Ser. On the other hand, amino acid digestibility in diet with faba beans+barley mix was lower (P < 0.05) compared with all the other diets, except for Arg, Asp, Lys, and Thr. It was concluded from the current studies that there is scope for using the assayed legumes, co-products, and quinoa in broiler chickens to partly replace SBM as protein feedstuffs.

Effects of main cereal type and feed form on production performance, egg quality and egg sanitary indices of laying hens

1. The experiment was conducted to evaluate the effects of cereal types (maize or wheat) and feed forms (pelleted or mash feed) on production performance, egg quality and egg sanitary indices in laying hens.2. Three hundred and sixty hens (Jinghong No. 1) at 18 weeks of age were randomly assigned to four treatments with six replicates of 15 hens per replicate according to a 2 × 2 factorial design with two cereal types (maize or wheat) and two feed forms (pelleted or mash feed).3. Compared with the wheat-based diet, the maize-based diet improved (P < 0.05) average egg weight of laying hens. Yolk colour of hens fed with the maize-based diet was higher (P < 0.05) in comparison to those fed the wheat-based diet, while Haugh units were lower (P < 0.05) for the maize-based treatment. Egg mass and average daily feed intake of hens fed the pelleted diet were higher (P < 0.05) than of those fed the mash diet. However, the mash diet improved (P < 0.05) yolk colour compared with the pelleted diet. The percentage of dirty eggs for the wheat-based diet was higher (P < 0.05) than for the maize-based diet. The percentage of dirty eggs was higher (P < 0.05) in birds fed the pelleted diet compared with those fed the mash diet. There were interactions (P < 0.05) between cereal type and feed form, with regard to average egg weight and shell thickness.4. In conclusion, dietary cereal type affected average egg weight, yolk colour and Haugh units in eggs, while feed form influenced egg mass, average daily feed intake and yolk colour.

Effect of different types and levels of fat addition and pellet binders on physical pellet quality of broiler feeds

Two experiments were conducted to evaluate the effects of different types and levels of mixer-added fat (soybean oil: SO and calcium fat powder: CFP) and pellet binders (PBs: calcium lignosulfonate (CaLS) and bentonite (Ben)) on physical pellet quality (PPQ) parameters. PPQ included pellet durability index (PDI), pellet hardness, and pellet length of broiler diets processed under short-term conditioning. The first experiment had 4 treatments arranged as a 2 × 2 factorial with 2 types (SO and CFP) and 2 levels (1.5 and 3%) of mixer-added fat. In the second experiment, 22 treatments, combinations of 2 types of mixer-added fat (SO and CFP) at 3 levels (0, 1.5 and 3%) and 2 types of PB (CaLS = 0, 0.5, and 1% and Ben = 0, 1, and 2%), were arranged by a completely randomized design. PDI was measured by 2 devices: Pfost Tumbling box (PDIT) and Holmen NHP tester (PDIH). The results showed that the diets containing 1.5% CFP without PB had significant differences in all PPQ parameters. The results revealed that adding 0.5% CaLS to the 3% SO diets significantly enhanced PDIH, pellet hardness, and pellet length compared to other treatments. Moreover, 1.5% CFP diets with 2% Ben had significantly higher PDIT, PDIH, and pellet hardness among the treatments. Based on contour plots, different levels of Ben in the diets containing SO failed to create optimum PDIT values (>96%). However, 1.5 to 2.50% CFP diets without Ben had the optimum PDIT values. The optimum PDIT value was achieved by the diets containing 3% SO in the range of 0.21 to 0.56% CaLS. Furthermore, adding 0.5% CaLS to the diets containing less than 2.86% SO resulted in suboptimal PDIT values (<96%). The diets containing 1.5 to 2.50% CFP without CaLS had the optimum PDIT values. However, increasing CaLS levels more than 0.38% led to suboptimal PDIT values. Overall, these results indicated that the selection of appropriate PBs should be based on type and level of mixer-added fat.