Nutritional modulation of health, egg quality and environmental pollution of the layers

Effects of dietary protein-oxidized soybean meal and quercetin on gel properties, microstructure, molecular structure and proteomics of egg white in laying hens

This study investigated the effects of dietary protein-oxidized soybean meal (SBM) and quercetin on gel properties, microstructure, molecular structure and proteomics of egg white in laying hens. A total of 288 Hy-Line Gray laying hens (500 days) were assigned to three groups, basal diets, protein-oxidized SBM diet, and protein-oxidized SBM diet supplemented with 300 mg/kg quercetin. The results showed that dietary protein-oxidized SBM decreased egg albumen height, gel hardness, gumminess and chewiness, and free sulfhydryl levels, although differences were not significant (P > 0.05). Quercetin supplementation reversed above mentioned indicators (P < 0.05). Dietary protein-oxidized SBM significantly increased the protein secondary structure α-helix content, reduced β-turn content, and reduced foam capacity of egg white (P < 0.05), while dietary quercetin alleviated the corresponding index (P < 0.05). Quercetin improved the egg Haugh unit, potentially due to its ability to increase the levels of microfilament proteins.

Multiprotease supplementation in laying hen diets: Impact on performance, egg quality, digestibility, gut histomorphology, and sustainability

Laying hen responses to supplemental multiprotease on performance, egg quality, digestibility, gut histomorphology, nitrogen excretion, and economic performance of laying hens until 37 weeks of age were investigated. A total of 189 25-week-old Hy-Line Brown hens were housed in enriched cages (7 birds/cage) and randomly allocated to 1 of 3 diets with 9 replicates per treatment. Dietary treatments included: an adequate positive control- PC [met the breed and age standards for crude protein (CP) and amino acids (AA)]; negative control- NC (90 % CP and AA requirement); and NC supplemented with multiprotease - NCMP. Multiprotease was supplemented at 300 g/t of feed equating to 2400 U/kg. Egg production rate and feed intake were not altered (P > 0.10) by the dietary treatments. Between 25 and 37 weeks of age (woa), the NCMP diet reduced the feed conversion ratios by 3 % (1.91 vs 1.97; P < 0.05) in comparison to the NC diet while improving (P < 0.05) the egg weights by 3 % (58.56 vs 56.68); Haugh units by 2 % (91.78 vs 90.20); and breaking strength by 1 % (4.65 vs 4.61). Marginally intensified yolk color and albumen height (P < 0.10) were also observed with the NCMP diet. Furthermore, the NCMP diet marginally improved the villus height, width, and absorptive surface area (P < 0.10) relative to NC. Multiprotease-supplemented NCMP diet improved (P < 0.05) the digestibility of crude protein; and amino acids including lysine, methionine, phenylalanine, isoleucine, leucine, glutamine, tyrosine, relative to the NC diet. Lowered AA/CP diets (NC and NCMP) reduced the N excreted and feed costs (P < 0.05) relative to the PC diet. Multiprotease increased the returns on investment (P < 0.10), and nitrogen retained in egg (P < 0.05) from 25- 37woa. Conclusively, feeding reduced CP/AA diets maintained the egg production rate while reducing the N excreted and feed costs. Multiprotease modulation of ileal absorptive capacity and nutrient digestibility is linked to improved feed efficiency, egg quality, and revenue estimates of supplemented hens.

The inclusion of insect meal from Hermetia illucens larvae in the diet of laying hens (Hy-line Brown) affects the caecal diversity of methanogenic archaea

The effect of the dietary inclusion of Hermetia illucens larvae meal on the diversity of the methanogenic archaea in the caecum of laying hens (Hy-line Brown) was investigated using molecular methods. A total of 27 hens, selected equally for slaughter from 162 birds which were divided equally into 3 treatment groups including control group C with a diet containing corn-soybean meal and 2 experimental groups, HI25 and HI50, in which 25% and 50% of the soybean meal protein was replaced by the protein from a Hermetia illucens larvae meal, respectively. At 40 weeks of age, the methanogenic community of caecal content of 9 hens per group was analyzed using a 16S rRNA gene clone library. A total of 108 positive clones, 35 from the control group, 44 from the HI25 group and 29 from the HI50 group, were analyzed by Sanger sequencing. Methanomicrobiales, Methanobacteriales and Methanomassiliicoccales were the main orders found in groups C and HI25. Methanomassiliicoccales was absent in the HI50 group, which was dominated by the order Methanobacteriales. At the species level, Methanobrevibacter woesei was the most prevalent species in all three groups regardless of diet. Some species were found exclusively either in the control group (Methanogenic archaeon CH1270) or in the HI25 group (Methanorbis furvi strain Ag1). Methanogenic diversity was significantly lower in the HI50 group compared to the control and HI25 groups and Methanomassiliicoccaceae archaeon DOK was completely suppressed in HI50 group. Our preliminary results indicate that ingestion of Hermetia illucens larvae meal has considerable effect on the methanogenic community, promoting the abundance of Methanobrevibacter woesei and suppressing Methanomassiliicoccaceae archaeon DOK in the caeca of laying hens.

Multi-omics analyses reveal that sirtuin 5 promotes the development of pre-recruitment follicles by inhibiting the autophagy-lysosome pathway in chicken granulosa cells

The development of pre-recruitment follicles plays a critical role in determining egg-laying performance in poultry. This study combines proteomic and metabolomic analyses to explore changes in proteins and metabolites, to elucidate key regulatory mechanism involved in chicken pre-recruitment follicular development. Histological examination revealed a significant increase in yolk deposition in small yellow follicles (SYF) compared to small white follicles (SWF). Metabolomics analysis identified significantly enriched differential metabolites (DMs) between SWF and SYF in pathways such as Lysosome, Ferroptosis, Biosynthesis of unsaturated fatty acids, and Tryptophan metabolism. Particularly, Adenosine-5'-Diphosphate (ADP) was downregulated during follicular recruitment and was significantly enriched in the lysosome pathway. Proteomic analyses revealed that differentially expressed proteins (DEPs) in SWF and SYF were enriched in pathways including Lysosome, Glutathione metabolism, Cholesterol metabolism, Arginine and proline metabolism, and amino acid biosynthesis. Among these DEPs, NAD-dependent protein deacetylase sirtuin 5 (SIRT5) was significantly upregulated, while lysosomal-associated membrane protein 1 (LAMP1) was down-regulated during the development of pre-recruitment follicles. SIRT5 was linked to the negative regulation of reactive oxygen species metabolism, whereas LAMP1 was associated with lysosome and autophagy pathways. Further validation experiments demonstrated high expression of SIRT5 in SYF, particularly in granulosa cells (GCs). Silencing SIRT5 in GCs resulted in increased ROS production and upregulated expression of autophagy-related proteins LC3Ⅱ and Beclin1, as well as lysosome markers LAMP1. Conversely, lipid droplet deposition and p62 expression were suppressed. inhibited. Taken together, these findings suggest that SIRT5 upregulation promotes the development of pre-recruitment follicles by inhibiting the autophagy-lysosome pathway in chicken GCs.

Effects of purple sweet potato polysaccharide on performance, egg quality characteristics, jejunal morphology, and gut microbiota of Hy-Line Brown laying hens

This study was conducted to investigate the effects of dietary purple sweet potato polysaccharide (PSPP) supplementation on production performance, egg quality characteristics, jejunal morphology, and gut microbiota modulation of Hy-line Brown laying hens. A total of 288 23-wk-old Hy-line Brown laying hens were randomly divided into 1 of the 4 dietary treatment groups, with 6 replicates and 12 laying hens per replicate. The 4 groups were fed basal diet supplemented with varying concentrations of PSPP (0, 1, 2, or 4 g/kg) for 6 wks. At the end of the feeding trials, eggs were collected for egg quality analysis, jejunal samples were collected for morphology assessment, and cecal content was analyzed by 16S rRNA high-throughput sequencing to determine intestinal microbiota. Experimental treatments did not differ regarding laying performance and egg quality. However, polynomial contrast analysis showed that there was a linear decrease (P = 0.042) in yolk color. The jejunal morphology did not differ among the treatment groups. The alpha and beta diversity were not different between the treatment groups. The cecal microbiota was dominated by Bacteroidota and Firmicutes at the phylum level and Bacteroides at the genus level. The relative abundance of Firmicutes was increased (P = 0.012) and Bacteroidota was decreased (P = 0.009) in the cecal content of PSPP2. Firmicutes to Bacteroidota ratio increased (P = 0.005) in the PSPP2 group. Polynomial contrast analysis showed that PSPP had a quadratic effect on Firmicutes to Bacteroidota ratio (P = 0.004) and on the relative abundance of Firmicutes (P = 0.006) and Bacteroidota (P = 0.006). At the genus level, increasing PSPP level showed a pattern of linear increase (P = 0.046) in [Ruminococcus]_torques_group and linear decrease (P = 0.015) in the Rikenellaceae_RC9_gut_group. It can be concluded that PSPP altered the gut microbiota, but did not influence jejunal morphology or laying performance and egg quality of laying hens. Further research is recommended to fully understand the potential and determine the optimal level of PSPP in laying hens.

Effects of Different Levels of Green Tea Powder on Performance, Antioxidant Activity, Egg Mass, Quality, and Cecal Microflora of Chickens

This study was conducted to investigate the effects of different levels of Green Tea Powder on the performance, egg quality, serum immune and antioxidant indices, and cecal microflora of 300-day-old Chishui black-bone chickens during the peak laying period. A total of 360 Chishui black-bone chickens were selected as the experimental animals. They were randomly allocated into four groups: the control group (CON), trial group I (T1), trial group II (T2), and trial group III (T3), each group with six replicates and 15 hens in each replicate. The control group was fed a basal diet, and the experimental groups were fed a basal diet supplemented with 0.8%, 1.6%, and 2.4% Green Tea Powder, respectively. The accommodation period was 14 d, and the experimental period was 60 d. The statistical software SPSS was used to perform a one-way analysis of variance (ANOVA) on the experimental data, and Duncan's method was used to perform multiple comparisons among groups. The results showed the following: compared with those of the control group, the average daily gain of the laying hens significantly decreased in the 1.6% Green Tea Powder group (p < 0.05); adding Green Tea Powder significantly reduced the content of malondialdehyde in the serum (p < 0.05), and the addition of 0.8% tea leaves significantly increased the immunoglobulin M and immunoglobulin A contents (p < 0.05); the egg yolk weight, eggshell thickness, eggshell strength, and yolk color of the laying hens significantly decreased in the 1.6% Green Tea Powder group (p < 0.05), and the addition of Green Tea Powder at the level of 2.4% significantly increased the percentage of umami, essential, and total amino acids (p < 0.05); and the structure of intestinal microorganisms was improved, and the abundance of Bacteroidetes and Bacteroidaceae significantly increased, while the abundance of Firmicutes and Lachnospiraceae significantly decreased (p < 0.05).

Effects of inclusion of the blend of essential oils, organic acids, curcumin, tannins, vitamin E, and zinc in the maternal diet, and of incubation temperature on early and late development of quail

The maternal diet and egg incubation temperature are some of the factors that can influence the embryonic development and performance of the newly chicks at 15 d of age. This study evaluated the effects of adding a blend of organic acids, essential oils, curcumin, tannins, vitamin E, and zinc microencapsulated in to the diet of female quails (Coturnix coturnix japonica) on their productive, reproductive performance and redox parameters of their eggs and the interaction of maternal diet × incubation temperature on embryo (E16 and E18) and chicks development. At 98 d of age, 64 female quails with a mean body weight of 150 g ± 0.5 were distributed into two treatments: a Basal diet or a diet supplemented with blend (Sannimix). The eggs from each female were incubated at 37.5°C (Control) and 38.5°C (High Temperature) throughout the incubation period. After hatching, chicks were distributed in a 2 (maternal diet) × 2 (incubation temperature) factorial design. Female quails supplemented with Sannimix showed better productive and reproductive performance and produced higher-quality embryos. Their offspring had greater weight at hatch and at 15 d of age. The eggs and offspring of supplemented with Sannimix female quails showed better oxidative stability. At E16 and E18, High Temperature increased yolk sac utilization and gene expression of the growth hormone receptor (GHR). At E16, embryos from supplemented with Sannimix female quail had higher expression of insulin-like growth factor type I (IGFI) and heat shock protein 70 kDa genes. At 15 d of age, highest expression of the GHR and IGFI genes was observed in chicks from female quails fed the Sannimix diet, regardless of incubation temperature. Regarding the maternal diet × incubation temperature an improved result was observed for chicks from female quails fed with Sannimix even when eggs are exposed to High Temperature during the incubation. The supplementation of quail diets with blend Sannimix improves productive and reproductive performance, egg quality and their embryos, as well as their offspring quality.

Influence of rosehip (Rosa canina L.) leaves as feed additive during first stage of laying hens on performances and egg quality characteristics

This study aimed to evaluate the effects of rosehip leaves (RL) supplementation on the production performances and egg quality of laying hens during the first stage of laying. For that, 90 Lohmann Brown Classic hens, aged 26 wk, were randomly assigned to 3 dietary treatments as follows: a control diet (RL0), an experimental diet containing 0.5% rosehip leaves (RL0.5), and an experimental diet containing 1% rosehip leaves (RL1). The laying hens were accommodated in an experimental hall with identical pens (3.96 m2), and controlled microclimate conditions. The dietary treatments were administered for a 6-wk experimental period (26-32 d of age). During this time, production performance of hens was recorded. To assess the impact of RL on egg weight and its components evolution, egg yolk and albumen color, and primary chemical composition of egg constituents were determined every 2 wk. The effect on egg yolk fatty acids profile was determined only at the end of the trial. The results showed that RL0.5 and RL1 dietary treatments significantly improved laying rate, feed conversion ratio and egg mass compared with RL0 group. A significant effect on egg weight and its components was observed only over time, showing that RL has no effect on these parameters. Significant changes in egg yolk coloration were observed over time, with significant increases in L*, a* and b* chromomeric parameters in both RL0.5 and RL1 compared to RL0. Significant alterations were obtained from the sum of egg yolk fatty acids. The RL1 egg yolk presented significantly higher n-3, and significantly lower n-6 fatty acids, compared with both RL0 and RL0.5. Further research is warranted to explore the long-term effects of rosehip leaf supplementation on laying hens performance and egg quality.

Immunological Response and Nutritional Effects of Lactobacillus spp.-fermented Garlic on Turkey Broilers

In the era of free antibiotics used in animal production, the application of feed additives should be prioritized to improve poultry health and production.  The present study was conducted to evaluate the influences of garlic fermented by Lactobacillus spp. on the growth rate, intestinal microorganisms, and immune response of turkey broilers. A completely randomized design was used, involving 90 turkey broilers aged 1-56 days, with five treatments and three replicates per treatment. The birds were given feed and water ad libitum for the entire experiment period. The treatments included the supplementation of aqueous extract from fermented garlic (FG) to drinking water. The results showed that broilers supplemented with 0.8% FG exhibited the largest final body weight (1,158 g/bird), body weight gain (19.64 g/bird/day), and significantly improved feed conversion ratio (1.962) while decreasing the feed intake of turkey broilers from to 1-56 days. The immune organ indices, including the spleen, thymus, and bursa of Fabricius indices, were increased in the 0.6% FG treatment group (P<0.05), while antibody titers (at 28 and 42 days of age) were improved in the 0.6% and 0.8% FG treatments (P<0.05). Clostridium perfringens and Salmonella spp. were not detected in the intestines of these birds, while the amount of Escherichia coli was reduced (P<0.05) and Lactobacillus spp. increased (P>0.05) without a significant effect. It can be concluded that supplementation with 0.8% FG improved growth performance, and 0.6% FG may enhance the immunity of turkeys. Moreover, 0.6% and 0.8% FG could be widely used for poultry production.

Liver Antioxidant Capacity and Steatosis in Laying Hens Exposed to Various Quantities of Lupin (Lupinus angustifolius) Seeds in the Diet

Despite the many beneficial properties of legume plants, their use in diets for poultry is limited by the presence of antinutritional factors. The aim of the study was to determine the activity of DT-diaphorase, ethoxycoumarin O-deethylase, and catalase, and the concentration of malondialdehyde in liver tissue, as well as the activity of SOD and CAT in the serum of Hy-line Brown hens fed a diet supplemented with various doses of Lupinus angustifolius seeds. The results indicate that the use of large amounts of lupin in the diet resulted in an increase in MDA concentration in the liver and the lipid vacuolization of hepatocytes. A significant increase in DTD activity was observed in chickens receiving 15% lupin. Regardless of lupin dose, no increase in SOD activity was observed in chicken serum after 33 days of the experiment. From the 66th day of the experiment, an increase in catalase activity in the serum of laying hens was observed, while low activity of this enzyme was found in the liver. It can be concluded that the short-term use of lupin in the diet of laying hens does not affect the activity of antioxidant enzymes and, therefore, does not affect the oxidative-antioxidant balance of their body.

Effects of dietary supplementation with Radix Isatidis polysaccharide on egg quality, immune function, and intestinal health in hens

This study aimed to investigate the effects of supplementing laying hen diets with Radix Isatidis Polysaccharide (RIPS) on egg quality, immune function, and intestinal health. The research was conducted using 288 Hyland Brown hens, which were randomly assigned to four dietary treatments: control (without RIPS), low dose (200 g/t), medium dose (500 g/t), and high dose (1000 g/t) of RIPS. Each dietary treatment was administered to eight replicates of nine hens for nine weeks. The results revealed that RIPS inclusion in diets significantly improved egg quality parameters such as egg shape index, yolk color, haugh unit, and protein height (P < 0.05). Additionally, RIPS supplementation enhanced immune function as evidenced by an alteration in serum biochemical parameters, an increase in the spleen index, and a decrease in the liver index. Further, an evaluation of intestinal health showed that RIPS fortified the intestinal barrier, thus increasing the population of beneficial intestinal bacteria and reducing the abundance of harmful ones. Such mechanisms promoted intestinal health, digestion, and nutrient absorption, ultimately leading to enhanced egg quality. In conclusion, supplementing laying hen diets with RIPS has been demonstrated to improve egg quality by boosting immunity and optimizing intestinal digestion and absorption.

Influence of the genotype of the hen (Gallus gallus domesticus) on main parameters of egg quality, chemical composition of the eggs under uniform environmental conditions

The objective of this study was to identify and compare the quality characteristics and concentrations of various compounds in eggs from several pure breeds and lines of hens reared under the same environmental conditions and fed a commercial feed. A total of 280 hens aged 52 to 56 wk belonging to 14 different breeds or lines of hens worldwide were included in this study. Their eggs were characterized by wide differences in various egg quality parameters. Breeds and lines of hens with a higher lutein content in eggs were characterized by a lower beta-carotene content (e.g. Hy line brown, Cochin miniature, Ayam Cemani) (P < 0.001). Additionally, vitamin D, cholesterol, and fatty acid contents were also different between eggs, from 1.51 to 1.79 μg/100g; from 14.1 to 15.4 mg/g fat, PUFA from 19.6 to 22.8 g/100g fat, and SFA from 32.8 to 37.8 g/100g fat respectively (P < 0.001). Lysozyme content also exhibited significant variation among breeds, with some showing a 2-fold higher content in eggs compared to others (0.31% - cochin miniature, 0.66% Faverolle) (P < 0.001). Our study demonstrated that intensively selected hen breeds like Hy-line Brown Hybrid had an improved egg quality seen by the increase in many parameters (e.g., egg weight, Haugh unit, Lutein, vitamins D, MUFA) compared to pure breed hens. In conclusion, genetic differences between breeds and lines of hens have a significant impact on the quality of eggs.

Dietary protein levels during 12 to 26 wk improve the growth performance, bone quality, and testosterone in Pearl Gray male guinea fowl (Numida meleagris)

Guinea fowl (Numida meleagris), although native to Africa and despite its many potentials, does not represent the dominant species on the continent because of its seasonal reproductive nature and high keets mortality. This study was conducted to assess the effect of crude protein levels on growth performance, bone characteristics and reproductive activity of Pearl Gray male breeder guinea fowl from 12 to 26 wk of age. A total of 120 twelve-wk-old guinea fowls were randomly allotted to 3 dietary treatments with 8 replicates each and 5 birds per replicate using a completely randomized design. The dietary treatments comprised low level (LL), normal level (NL), and high level (HL) with diets respectively containing 15, 17, and 19% crude protein (CP). The results showed that guinea fowl in the HL treatment had a significantly lower feed conversion ratio (P = 0.008) than those in the other treatments. The birds fed the HL diet had significantly higher concentrations of testosterone (P < 0.05) than in the other treatments. High levels of calcium and phosphorus were observed in the femur of the HL group relative to the LL group. The birds in the LL treatment had a significantly higher (P = 0.007) femur robusticity index than those in the HL treatment. In conclusion, feeding 19% crude protein to Pearl Gray male guinea fowl from 12 to 26 wk of age improves growth performance, the density and strength of the femur and tibia and the reproductive tract. The CP level for the best performance of male guinea fowl from 12 to 26 wk of age is 19%.

Improvement of egg internal quality of local ducks through star gooseberry leaf meal inclusion in ration

Objectives

The use of dried star gooseberry leaf extract (DSGLE) in rations and its effects on the egg internal quality of local ducks were examined.

Materials and Methods

A total of 100 9-month-old local ducks weighing 1,406.25 ± 211.32 gm were randomly allocated into 5 treatments and 5 replicates in a completely randomized design. The birds were reared in 25 battery cages (4 birds each) and fed rations containing 0, 0.5%, 1.0%, 1.5%, and 2.0% DSGLE.

Results

Eggs of ducks fed DSGLE had significantly lower saturated fatty acid (SFA) (30.66%-32.53%) than those of control ducks (36.23%). Egg polyunsaturated fatty acids (PUFA) increased from 2.29% (control) to 2.61% (2.0% DSGLE) and 2.76% (1.5% DSGLE), while egg monounsaturated fatty acid (MUFA) contents were not significantly different. The fatty acids of the whole edible part of eggs (albumen + yolk) were composed mainly of MUFA (40.19%-44.34%), followed by SFA (30.66%-36.22%), and PUFA (2.29%-2.76%). Malondialdehyde contents were reduced from 6.07 to 4.92 µg/gm (19%) in egg yolk and from 1.50 to 0.62 µg/gm (59%) in egg white, and thiobarbituric acid reactive substances values of the eggs were reduced from 0.93 to 1.65 (77%). The egg cholesterol level of ducks fed 2% DSGLE (21.94 mg/gm) was about 28.5% lower than that of eggs from control ducks (30.67 mg/gm) of eggs of control ducks. The egg white and egg yolk protein contents (12.31% and 16.35%) of treated ducks were lower than those in the control group (13.58% and 17.47%).

Conclusion

The inclusion of SGLE in rations could be used to produce healthy duck eggs with no oxidative damage.

The impact of digestible lysine and sulfur amino acids on eggshell quality and egg weight control in old ISA brown hens during 62 to 74 wk

Modifying dietary amino acids has been proposed as a strategy to improve eggshell quality by slowing down increases in egg weight (EW). This study aimed to investigate the effects of different levels of digestible lysine (dLYS) and ratios of digestible sulfur amino acids (dTSAA) to dLYS on performance and eggshell quality in ISA brown hens. A total of 288 hens were individually housed and assigned to 8 treatments, which combined 2 levels of dLYS (5.9 and 5.5 g/kg) with 4 ratios of dTSAA:dLYS (90, 85, 80, and 75) in a factorial arrangement. The study lasted 12 wk, starting at 62 wk of age. The number of eggs was not affected by the interaction between dLYS and dTSAA:dLYS or their main effect. However, the interaction between dLYS and dTSAA:dLYS showed that reducing the dTSAA:dLYS ratio from 85 to 75 when hens were fed 5.5 g/kg of dLYS resulted in a lower EW. Conversely, when hens were fed 5.9 g/kg of dLYS, no significant difference was found in EW among the different ratios of dTSAA:dLYS. Although there was no interaction between the levels of dLYS and dTSAA:dLYS on eggshell quality, reducing the dLYS level from 5.9 to 5.5 slowed down the deterioration in eggshell-breaking strength and eggshell thickness, regardless of the dTSAA:dLYS ratio. These findings suggest that adjusting dietary dLYS while maintaining the dTSAA:dLYS ratio of no less than 85 may be an effective strategy for decelerating the deterioration of eggshell quality in laying hen operations without impacting the egg production rate.

Effects of dietary protein levels on performance, nitrogen excretion, and odor emission of growing pullets and laying hens

The objective of this study was to determine the effects of dietary crude protein (CP) levels on production performance, nitrogen balance, and odor emission of excreta in growing pullets and laying hens from 13 to 32 wk of age. Two hundred and forty pullets (Hy-Line Brown) were randomly assigned to 1 of 4 dietary groups with 10 replicates per group, and 6 birds per replicate. Experimental diets were formulated to contain 4 graded CP levels in the diets of pullets ranging from 180, 160, 140, and 120 g/kg of diet during 13 to 18 wk (phase 1) and in the diets of laying hens from 190, 170, 150, and 130 g/kg of diet during 19 to 32 wk (phase 2). The limiting amino acids including lysine, methionine, and threonine were supplemented to maintain constant equal amino acid concentrations in all experiment diets. In phase 1, decreasing dietary CP levels did not affect growth performance but increased (linear and quadratic effect, P < 0.05) the relative abdominal fat contents and triglyceride concentration in serum samples. High-density lipoprotein cholesterol in serum samples decreased as the CP levels decreased in the diets of pullets. Dietary CP levels quadratically increased (P < 0.05) the villus height and the villus height to crypt depth ratio but did not affect tibia traits and relative organ weights in pullets at 18 wk. Apparent digestibility of dry matter and ether extract increased with decreasing dietary CP levels in pullets. Graded CP levels linearly increased the digestibility of dry matter, CP, and ether extracts but lowered that of crude ash in laying hens. Nitrogen excretion was linearly decreased (P < 0.05) as the dietary CP levels decreased in both pullets and laying hens. Dietary CP levels only affected carbon dioxide emission in pullets. In phase 2, dietary CP levels did not affect growth performance and the ages at first egg laying and to reach 50% egg production in laying hens. However, egg weights were decreased (linear and quadratic effect, P < 0.05) as the dietary CP level decreased in laying hens. Increasing dietary CP levels increased Haugh unit at 26 wk but lowered corticosterone concentrations in yolk samples at 22 wk. Collectively, this study shows that dietary CP levels could be decreased to reduce nitrogen excretion without adverse effects on performance and egg quality of growing pullets and laying hens.

Comparison of the effect of quercetin and daidzein on production performance, anti-oxidation, hormones, and cecal microflora in laying hens during the late laying period

This study aims to compare the effect of quercetin and daidzein on production performance, anti-oxidation, hormones, and cecal microflora in laying hens during the late laying period. A total of 360 53-week-old healthy Hyline brown laying hens were randomly divided into 3 groups (control, 0.05% quercetin, and 0.003% daidzein). Diets were fed for 10 wk, afterwards 1 bird per replicate (6 replicates) were euthanized for sampling blood, liver and cecal digesta. Compared with the control, quercetin significantly increased laying rate and decreased feed-to-egg weight ratio from wk 1 to 4, wk 5 to 10, and wk 1 to 10 (P < 0.05). Quercetin significantly increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased catalase (CAT) activity and malondialdehyde (MDA) content in serum and liver (P < 0.05) and increased content of total antioxidant capacity (T-AOC) in liver (P < 0.05). Quercetin increased content of estradiol (E₂), luteinizing hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH), insulin-like growth factor 1 (IGF-1), triiodothyronine (T₃) and thyroxine (T₄) in serum (P < 0.05). Quercetin significantly decreased the relative abundance of Bacteroidaceae and Bacteroides (P < 0.01) and significantly increased the relative abundance of Lactobacillaceae and Lactobacillus (P < 0.05) at family and genus levels in cecum. Daidzein did not significantly influence production performance from wk 1 to 10. Daidzein significantly increased SOD activity and decreased CAT activity and MDA content in serum and liver (P < 0.05), and increased T-AOC content in liver (P < 0.05). Daidzein increased content of FSH, IGF-1, T₃ in serum (P < 0.05). Daidzein increased the relative abundance of Rikenellaceae RC9 gut group at genus level in cecum (P < 0.05). Quercetin increased economic efficiency by 137.59% and 8.77%, respectively, compared with daidzein and control. In conclusion, quercetin improved production performance through enhancing antioxidant state, hormone levels, and regulating cecal microflora in laying hens during the late laying period. Quercetin was more effective than daidzein in improving economic efficiency.

Natural Multi-Enriched Eggs with n-3 Polyunsaturated Fatty Acids, Selenium, Vitamin E, and Lutein

The research investigates the possibilities of enriching eggs with n-3 polyunsaturated fatty acids, selenium, vitamin E, and lutein. The research was carried out on 100 TETRA SL laying hens divided into two groups (C and E). Hens in treatment C (control group) were fed a standard feeding mixture that contained 5% soybean oil, 0.32 mg/kg organic selenium, 25.20 mg/kg vitamin E, and 20.5 mg/kg lutein (Marigold flower extract). Hens in treatment E (experimental group) were fed a mixture in which soybean oil was replaced by 1.5% fish oil + 1.5% rapeseed oil + 2.0% linseed oil. The content of other nutricines amounted to 0.47 mg/kg organic selenium, 125.2 mg/kg vitamin E, and 120.5 mg/kg lutein. Portions of total n-3 polyunsaturated fatty acids in enriched eggs were significantly increased when compared to conventional eggs (480.65:204.58 mg/100 g; p < 0.001). The content of selenium, vitamin E, and lutein was significantly higher (p < 0.001) in enriched eggs than in conventional eggs. The content of selenium in egg albumen was increased by 1.81 times, and in the yolk, it was increased by 1.18 times. At the same time, the content of vitamin E was 2.74 times higher, and lutein was 8.94 times higher in enriched eggs than in conventional eggs.

R- Is Superior to S-Form of α-Lipoic Acid in Anti-Inflammatory and Antioxidant Effects in Laying Hens

The development of single enantiomers with high efficiency and low toxic activity has become a hot spot for the development and application of drugs and active additives. The aim of the present study was to investigate the effectiveness of the application of α-lipoic acid with a different optical rotation to alleviate the inflammation response and oxidative stress induced by oxidized fish oil in laying hens. Sixty-four 124-week-old Peking Red laying hens were randomly allocated to four groups with eight replicates of two birds each. The normal group was fed basal diets supplemented with 1% fresh fish oil (FO), and the oxidative stress model group was constructed with diets supplemented with 1% oxidized fish oil (OFO). The two treatment groups were the S-form of the α-lipoic acid model with 1% oxidized fish oil (OFO + S-LA) and the R-form of the α-lipoic acid model with 1% oxidized fish oil (OFO + R-LA) added at 100 mg/kg, respectively. Herein, these results were evaluated by the breeding performance, immunoglobulin, immune response, estrogen secretion, antioxidant factors of the serum and oviduct, and pathological observation of the uterus part of the oviduct. From the results, diets supplemented with oxidized fish oil can be relatively successful in constructing a model of inflammation and oxidative stress. The OFO group significantly increased the levels of the serum inflammatory factor (TNF-α, IL-1β, IL-6, and IFN-γ) and the oxidative factor MDA and decreased the activity of the antioxidant enzyme (T-AOC, T-SOD, GSH-Px, GSH, and CAT) in the oviduct. The addition of both S-LA and R-LA significantly reduced the levels of serum inflammatory factors (TNF-α, IL-1β, IL-6, and IFN-γ), increased the activity of antioxidant indexes (T-AOC, T-SOD, GSH-Px, GSH, and CAT), and decreased the MDA contents in the serum and oviduct. Meanwhile, the supplementation of S-LA and R-LA also mitigated the negative effects of the OFO on the immunoglobulins (IgA and IgM) and serum hormone levels (P and E2). In addition, it was worth noting that the R-LA was significantly more effective than the S-LA in some inflammatory (IL-1β) and antioxidant indices (T-SOD, GSH, and CAT). Above all, both S-LA and R-LA can alleviate the inflammation and oxidative damage caused by oxidative stress in aged laying hens, and R-LA is more effective than S-LA. Thus, these findings will provide basic data for the potential development of α-lipoic acid as a chiral dietary additive for laying hens.

Assessment of Environmental Impacts from Different Perspectives-Case Study of Egg Value Chain System in Serbia

The environmental performance of various aspects of animal origin food supply chains has been the focus of research in recent years, and has provided useful information. However, there were no studies that covered the entire egg supply chain from different perspectives. The aim of this study was to analyze the majority of environmental impacts in the table egg supply chain comprising of three subsystems: farms, retail outlets and households, with quantification of each individual subsystem and the entire supply chain. All data were gathered from 30 farms, 50 retail stores and 300 households in Serbia. In parallel, the perception and ranking of environmental impacts along the supply chain were also evaluated. Finally, the quality function deployment for the environment was used to determine the degree of correlation between the set of environmental requirements and the identified environmental impacts. Results revealed that the greatest environmental impacts come from the production of feed for laying hens and the use of natural resources, and they contribute the most to the pollution of each individual environmental indicator. Additionally, the results show the differences in the environmental impacts of each individual subsystem and identify opportunities to mitigate them through the optimization of animal feed, energy consumption and household food waste management. The overall perspective of the egg supply chain points to climate change effects as the most important. The differences in the perceptions of environmental impacts along the entire egg supply chain suggest the need for promotion of mitigation strategies to all stakeholders that would encourage them to achieve sustainable development goals.

Amino acid requirements for laying hens: a comprehensive review

The main aim of this review is to consolidate the relevant published data examining amino acid requirements of layer hens and to reach a new set of recommendation based on these data. There are inconsistences in lysine, sulphur-containing amino acids, threonine, tryptophan, branched-chain amino acids, and arginine recommendations in data that have surfaced since 1994. This review finds that breed, age, basal diet composition, and assessment method have contributed toward inconsistencies in amino acid recommendations. Presently, the development of reduced-protein diets for layer hens is receiving increasing attention because of the demand for sustainable production. This involves quite radical changes in diet composition with inclusions of nonbound, essential and nonessential amino acids. Increasing inclusions of nonbound amino acids into layer diets modifies protein digestive dynamics, and it may influence amino acid requirements in layer hens. This review considers present amino acid recommendations for layer hens and proposes refinements that may better serve the needs of the layer industry in the future.

Folate Content and Yolk Color of Hen Eggs from Different Farming Systems

This study aimed to compare folate contents in hen eggs from four different farming systems, namely organic, free range, barn, and cage one. Folate retention during egg boiling was studied as well. The contents of individual folate vitamers were determined using the high-performance liquid chromatography method (HPLC), following trienzyme treatment. Folate content in eggs differed significantly (p < 0.05) due to the rearing system, with the highest mean content determined in the eggs from organic farming (113.8 µg/100 g). According to this study, one egg (60 g) may provide 40-86 µg of folates, which corresponds to 10-22% of the recommended daily intake for adults, 400 µg according to the Nutrition Standards for the Polish Population. The predominant folate form found in egg was 5-methyltetrahydrofolate, which showed considerably greater stability under boiling compared to 10-formylfolic acid present in a lower amount. In most eggs tested, the losses in total folate content did not exceed 15%. The color of yolk of the most folate-abundant organic eggs, had the highest value of lightness (L*) and the lowest value of redness (a*). This, however, does not correspond to consumer preferences of intense golden yolk color.

Nutritional significance of amino acids, vitamins and minerals as nutraceuticals in poultry production and health - a comprehensive review

Nutraceuticals have gained immense importance in poultry science recently considering the nutritional and beneficial health effects of their constituents. Besides providing nutritional requirements to birds, nutraceuticals have beneficial pharmacological effects, for example, they help in establishing normal physiological health status, prevent diseases and thereby improve production performance. Nutraceuticals include amino acids, vitamins, minerals, enzymes, etc. which are important for preventing oxidative stress, regulating the immune response and maintaining normal physiological, biochemical and homeostatic mechanisms. Nutraceuticals help in supplying nutrients in balanced amounts for supporting the optimal growth performance in modern poultry flocks, and as a dietary supplement can reduce the use of antibiotics. The application of antibiotic growth enhancers in poultry leads to the propagation of antibiotic-resistant microbes and drug residues; therefore, they have been restricted in many countries. Thus, there is a demand for natural feed additives that lead to the same growth enhancement without affecting the health. Nutraceuticals substances have an essential role in the development of the animals' normal physiological functions and in protecting them against infectious diseases. In this review, the uses of amino acids, vitamins and minerals as well as their mode of action in growth promotion and elevation of immune system are discussed.

Effect of supplementation with solid-state fermented feed in the diet of laying hens on egg qualitative variables

   The aim of this experiment was to evaluate the effect of the supplementation of laying hens diet with solid-state fermented feed on egg qualitative variables. The diet of laying hens was supplemented with 10% and 15% of solid-state feed fermented by the low filamentous fungal strain Mortierella alpina CCF 2861. For the trial, 30 Lohmann Brown classic layers, aged 17 weeks, were selected and individually weighed and divided into three groups (control and two experimental groups). The control group of laying hens was fed with basic feed mixture and the experimental groups received the same diet as a control group, but enriched with supplementation of solid-state fermented feed. The first experimental group was fed a diet supplemented with 10% of fermented feed and the second experimental group with 15% supplementation. The following egg qualitative variables were observed: the egg weight, Haugh units, quality grade, air cell depth, percentage of the shell, yolk and albumen, eggshell breaking force, pH of egg yolk and albumen, egg yolk colour, and antioxidant activity with the extent of lipid oxidation in egg yolk samples. The pH of yolk and albumen did not show differences between all examined eggs originating from the experimental groups of laying hens (p >0.05). The eggs from both experimental groups had a significantly higher eggshell hardness than eggs produced by the hens of the control group (p <0.05). Antioxidant activity of egg yolk of experimental samples increased with the supplementation of fermented feed in the diet of laying hens (p <0.05). The specific lightness of egg yolk colour increased significantly in the experimental group with 15% of supplementation (p <0.01). The obtained results showed that feeding laying hens with fermented feed positively affected the quality of produced eggs. This was the first study and further investigation before using the fermented feed in commercial laying hen farms is necessary.

Systematic Mapping of Research on Farm-Level Sustainability in Egg and Chicken Meat Production

The sustainability of future poultry production needs to be improved in order to meet global challenges. The global chicken population has expanded significantly in recent decades, due to increased human demand for eggs and chicken meat. Therefore, it is critically important to mitigate challenges to the sustainability of modern poultry production, such as pollution, the depletion of finite natural resources and animal welfare issues. This study systematically mapped the scientific literature on farm-level sustainability in egg and chicken meat production. The concept of sustainability was considered holistically, covering its economic, environmental and social dimensions, each consisting of a broad range of different aspects that may contradict or reinforce each other. The literature published between January 2000 and March 2020 with a geographical focus on Europe, North America and Australia–New Zealand, were included. The literature search resulted in a total of 428 hits, but after the exclusion of articles that did not match the scope of the study, only 26 papers remained for the systematic mapping. Of these, only three papers covered all three dimensions of sustainability. Aspects of economic sustainability were addressed in 10 papers, aspects of environmental sustainability in 18 papers, and aspects of social sustainability in 23 papers. The findings in this study are an important foundation for the discussion and prioritisation of future actions to increase knowledge of farm-level sustainability in egg and chicken meat production.

The Genus Allium as Poultry Feed Additive: A Review

The genus Allium, belonging to the family Amaryllidaceae has been known since ancient times for their therapeutic potentials. As the number of multi-drug resistant infections has increased due to in-feed antibiotic usage in poultry, the relevance of alliums as feed additives has been critically assessed. Garlic and the other Allium species, such as onions, leek, shallot, scallion, and chives, have been characterized to contain a plethora of bioactive compounds such as organosulfur compounds, polyphenols, saponins, fructans, and fructo-oligosaccharides. Consequently, alliums have been validated to confer antioxidant, antibacterial, antiviral, immunostimulatory, gut homeostasis, and lipid- as well as cholesterol-lowering properties in poultry. This review intends to summarize recent progress on the use of edible alliums as poultry feed additives, their beneficial effects, and the underlying mechanisms of their involvement in poultry nutrition. Perspectives for future research and limitations are also briefly discussed.

Evaluation of Quality of Eggs from Hens Kept in Caged and Free-Range Systems Using Traditional Methods and Ultra-Weak Luminescence

The paper presents the results of an evaluation of the quality of eggs from laying hens kept in caged and free range systems using traditional methods and ultra-weak luminescence (USL). It was found that the tested eggs were fresh and were characterized by the required quality, as demonstrated by analysis of the egg white and egg yolk. Eggs from free-range laying hens were characterized by an eight-fold higher emission of photons compared to eggs from caged hens, and they had over three times higher content of natural antioxidants in the form of carotenoids. Most probably, the higher number of photons emitted is associated with a higher content of biologically active substances in the material under study. Photon emission also varies in different ways depending on the specific hen breeding system. Differences in time in the identified maximum values of photon emission result from the composition of individual parts of the egg. Different times in which the emission peaks occurred for free-range eggs and for caged eggs were observed. The application of the USL method in order to confirm its usefulness in the assessment of food quality requires further research.

Dietary glycerol monolaurate supplementation for the modification of functional properties of egg white protein

BACKGROUND

Understanding the interactions between feed additives and the functional properties of egg white protein (EWP) may offer novel insights into the effects of feed additives on laying hens and may provide an alternative for modification of the functional properties of EWP by using laying hens as bioreactors. Glycerol monolaurate (GML) is widely used in the food industry as an effective antibacterial emulsifier. In this work, the effects of three doses of dietary GML supplementation (150, 300, and 450 mg kg^-1 hen) on the functional properties of EWP were investigated.

RESULTS

The hardness of EWP gels was significantly improved by 300 and 450 mg kg^-1 GML supplementation. Foaming capacity (FC) and foaming stability (FS) were increased after GML treatment; 450 mg kg^-1 GML supplementation showed the most significant improvements, with 44.82% in FC and 23.39% in FS. Stabilization of EWP-oil emulsions was also improved, supported by a slowed creaming process and the formation of smaller oil droplets. The heat denaturation temperature and rheological properties were also modified by dietary GML supplementation, implying improved thermal stability.

CONCLUSION

Our study demonstrated that GML supplementation has the potential to modify the functional properties of EWP, broadening the application of GML and providing a new perspective for evaluation of the efficacy of feed additives. © 2019 Society of Chemical Industry.

Family poultry: Multiple roles, systems, challenges, and options for sustainable contributions to household nutrition security through a planetary health lens

Achieving sustainable production of eggs by family poultry production systems that meet both environmental health and welfare standards is a complex endeavour. Humans have been raising different species of poultry for thousands of years across many different agroecological zones. The Food and Agriculture Organization of the United Nations has identified four different family poultry production systems: small extensive, extensive, semi‐intensive, and intensive. Each of these systems varies in terms of inputs, outputs, gender dimensions, poultry health and welfare, and environmental impacts. This paper addresses key issues associated with the production of family poultry eggs in support of both improved maternal and child nutrition and sustainable, nutrition‐sensitive agricultural practices. It provides an overview of the history of poultry raising; characteristics of the different family poultry production systems; challenges and solutions to poultry production in low‐ and middle‐income countries; poultry husbandry (including breeds, nutrition, and shelter); infectious disease prevention and control in line with national and international animal health regulations; and food safety (microbial pathogens, toxins, and egg storage). To ensure that bird, human, and environmental health can flourish, it is essential for interdisciplinary research and development teams to work in collaboration with communities to ensure the long‐term environmental and economic sustainability of family poultry production enterprises that are a good fit with local circumstances.

Chicken anaemia virus enhances and prolongs subsequent avian influenza (H9N2) and infectious bronchitis viral infections

Immunosuppressive viral diseases have a great economic importance in the poultry industry due to the increased susceptibility to secondary infections. Chicken anaemia virus (CAV) is one of the major immunosuppressive diseases in chickens. In addition, low pathogenic avian influenza (LPAI) of subtype H9N2 and infectious bronchitis (IB) viruses are among the most frequently reported respiratory viral diseases in poultry worldwide. In the present study, specific pathogen free chickens were used to understand the impact of CAV on secondary infection with LPAI-H9N2 or IB viruses. Clinical outcomes, viral shedding dynamics, and cytokine levels wereassessed. The results exhibit that chickens previously infected with CAV produceconsiderablyhigher titresof LPAI-H9N2 or IB viruses in the oropharyngeal swabs (P < 0.05), tracheas and kidneys. In addition, the immunologic effect of CAV provokedthe development of clinical signs of LPAI-H9N2 and IB virus infections. Moreover, results suggested that pre-infection with CAV directly correlated with elevated levels of IL-6 and IFNγ. These findings underline the importance of CAV pre-infection on LPAI-H9N2 or IB infection in chickens, and indicate that co-circulation of CAV can contribute to the spread and evolution of LPAI H9N2 and IB viruses.