Induced molting is process used by commercial producers to extend the reproductive life of a laying hen. Typically, producers deprive hens of feed for a period of 7-14 days while reducing the amount of light exposure to the hens. This allows for regression of the reproductive tract and for a second cycle of egg production to occur. However, induced molting by feed deprivation has been shown to increase the hen's risk of becoming infected with pathogenic bacteria, such as Salmonella. This increased risk could mean an increase in contaminated eggs or egg products, which causes concerns for public health. This combined with increasing pressure on egg producers from animal welfare organizations has prompted the investigation of diets that would provide available energy for the hens, while still inducing a molt that is economically advantageous to producers. Alfalfa, provided in meal or pelleted form, provides only 1/2 the metabolizable energy and 1/4 of the calcium required of a laying hen that is reproductively active. Due to the decrease in nutrients, alfalfa was investigated as an alternative to feed deprivation. Studies were conducted to assess egg quality, egg production, consumer acceptance, and hen physiology.

Induced molting is process used by commercial producers to extend the reproductive life of a laying hen. Typically, producers deprive hens of feed for a period of 7-14 days while reducing the amount of light exposure to the hens. This allows for regression of the reproductive tract and for a second cycle of egg production to occur. However, induced molting by feed deprivation has been shown to increase the hen's risk of becoming infected with pathogenic bacteria, such as Salmonella. This increased risk could mean an increase in contaminated eggs or egg products, which causes concerns for public health. This combined with increasing pressure on egg producers from animal welfare organizations has prompted the investigation of diets that would provide available energy for the hens, while still inducing a molt that is economically advantageous to producers. Alfalfa, provided in meal or pelleted form, provides only 1/2 the metabolizable energy and 1/4 of the calcium required of a laying hen that is reproductively active. Due to the decrease in nutrients, alfalfa was investigated as an alternative to feed deprivation. Studies were conducted to assess egg quality, egg production, consumer acceptance, and hen physiology.

The use of antibiotics as growth promotors in the food animal industry has led to the generation of antibiotic resistant microorganisms, which are a major health risk to humans. Therefore, bans and limitations, including the FDA’s veterinary feed directive, have been placed on the use of antibiotics as growth promotors, and there has been a push to find an adequate alternative. In the laying hen, probiotics and/or prebiotics have shown promise as they help promote the colonization of beneficial bacteria in the GI tract of the host, increase feed efficiency, increase egg production, and provide protection against pathogenic bacteria. In this feeding trial, Leghorn HyLine W36 hens were fed diets supplemented with either 0.05% IMW50(prebiotic), 0.05% CALSPORIN (probiotic), 0.05% IMW50 and 0.05% CALSPORIN, or a control diet with no prebiotic or probiotic additive. The birds were maintained on this diet from 1 day to 66 weeks of age, over which time feed intake and egg production was measured. From 37 to 65 weeks of age, every 3-5 weeks, egg quality was evaluated through specific gravity, egg weight, albumen height, and eggshell breaking force measurements. At 6, 16, 32, and 64 weeks of age, the microbiota population in the ileal digesta was evaluated using T-RFLP analysis methods. Then at 64 weeks of age, splenic IFN-γ, IL-6, IL-10, and IL-12 expression was measured by RT-qPCR. Unexpectedly, fluctuations in feed disappearance were observed, potentially linked to factors such as changes in diet type, temperature variations, feed wastage, or a technical error. Birds on CALSPORIN-containing diets showed resilience and maintained egg production during a decline in feed disappearance, suggesting enhanced capabilities in digesting larger particle sizes. However, there were trade-offs, as egg quality parameters slightly decreased in supplemented diets. CALSPORIN alone showed a promising effect on survival probability. Microbial diversity in the ileum increased with CALSPORIN, but the IMW50 alone led dysbiosis, possibly impacting infection resistance. Additionally, the combined supplementation of IMW50 and CALSPORIN may have introduced a disruption in immunological homeostasis.

A series of experiments were conducted to explore factors affecting transfer of value-added ingredients from the diet to table eggs, with the goal of contributing to improvements in the enrichment process. Flaxseed-based ω-3 PUFA enrichment did not reduce lutein enrichment. The combine enrichment of lutein and ω-3 PUFA had decresed lipid oxidation potential. Also, when fed a ω-3 PUFA diet, birds scored as energetic Efficient had longer and wider villi, resulting in greater absorptive surface area/villi than Non-efficient hens. However, histomorphological differences did not affect transfer of ω-3 PUFA from diet to egg. Finally, birds fed graded levels of ω-3 PUFA to characterize change in lipid profile of egg and blood plasma in time reached a plateau in total ω-3 PUFA/egg in 5.9 to 6.6d, with High birds reaching the target of 300 mg/egg in 5d. Egg enrichment can be modulated by changes to the hen diet. / Animal Science

he influence of two levels of yeast cell wall on phase one laying hen performance was investigated in this study. A total of 75 Lohmann W-36 replacement pullets, 17-weeks-old, were distributed among 75 laying hen cages (1 bird per pen). A total of 3 treatments were sequentially assigned to pens and each treatment had 25 replicates. Feeds were prepared according to the management guide for those birds and a single basal diet was divided into three treatments. First was the control basal diet only with no feed additives. The second was the basal diet supplemented with 250 ppm of yeast cell wall (YCW 250) and the third treatment was the basal diet supplemented with 500 ppm of yeast cell wall (YCW 500). Individual birds per cage served as the experimental unit for this study. Feed and water were offered ad libitum. Data were collected when birds were 21 weeks old and hen day egg production was > 90%. Treatment YCW 250 resulted in significantly higher egg weight than the control and YCW 500 treatment in the first and second production period and was higher than YCW 500 in the third and fourth production period. Feed consumed per dozen eggs was significantly lower in treatment YCW 500 versus treatment YCW 250, but not significantly lower than the control for the first production period and all treatments were not different from each other for the rest of the study. Average feed consumed per bird per day, and monthly cumulative egg production was not different between treatments. Period feed conversion ratios were lower for the second and fourth period (P = 0.15 and 0.18 respectively). There was no treatment effect on interior egg quality except for yolk color for the YCW 500 treatment in the fourth period which had significantly higher Roche color scores than the YCW 250 treatment. Specific gravity, egg shell thickness, egg shell weight, and percent shell weight were significantly higher in hens fed YCW 500 versus YCW 250. Egg shell breaking force was significantly higher in hens fed YCW 250 versus the control group. Overall, feeding a diet supplemented with yeast cell wall improved laying hen performance and 250 ppm YCW had the most significant influences, particularly with respect to increasing egg weight in early production laying hens.

No description available.

The enrichment of egg with folate is a viable option for supplying the general population of a food product rich in natural folates. However, attempts to increase the concentration of folate in egg beyond the achieved level of enrichment had been unsuccessful because egg folate reached a maximum plateau when folic acid (FA) was increased in the diet. Thus, experiments were conducted to determine the factors regulating the deposition of dietary FA into the eggs. In the first study, the effect of feeding equimolar intake of FA and 5-methyltetrahydrofolate (5-methylTHF), the biologically active form of folate; on egg folate concentrations, indices of folate status, and activities of folate-dependent enzymes was evaluated. Folic acid and 5-methylTHF demonstrated equivalent effects in enhancing the egg folate concentrations and improving the indices of folate status in the laying hen. The activities of folate-dependent enzymes were similar between the two forms of folate except for hepatic dihydrofolate reductase (DHFR) activity which increased in FA-fed birds compared to 5-methylTHF-fed birds. However, this demonstrated the ability of the laying hen to metabolically convert FA into its biologically active forms. Therefore, the influence of intestinal FA absorption in the regulation of FA deposition in the egg was subsequently evaluated. Using the in vitro everted intestinal sac technique, FA was absorbed in all regions of the intestine. Absorption was maximum at acidic pH 6.0, and increased in the duodenum and jejunum compared to the ileum and cecum. The rate of FA absorption in the jejunum diminished at higher FA concentrations. Therefore, further study was conducted to determine the regulation of FA absorption when levels of FA in the laying hen diet are increased. Supplementation of increased FA levels resulted to a down-regulation of FA absorption in the duodenum, but not in the jejunum of the laying hen. This down-regulation was not associated to a decreased mRNA gene expression of the duodenal folate transporters. Overall, decreased intestinal rate of FA absorption possibly associated to a post-transcriptional or translational regulation of specific folate transporters in the intestine of the laying hen may contribute to the saturation in the egg folate concentration.

We investigated the effects of dietary folic acid and age, on immunological parameters in laying hens challenged with LPS. 48 Shaver White hens at different ages were fed 2 wheat-soybean based diets with 0 or 4 mg supplemental FA per kg of diet for 8 wk. 6 hens from each dietary treatment were injected with 8 mg/kg body weight of LPS or saline and observed for 4 h. A few diet X challenge interaction were observed in young hens, whereas FA and LPS independently influenced a number of parameters. In older hens, there were very few diet X challenge interactions as well as effects of FA, whereas LPS affected several parameters. In conclusion, dietary FA influenced some immune responses in younger hens, but no such effects were observed in older hens. FA may modulate immune responses in laying hens under acute LPS challenge which could be tissue and age dependent.

The enrichment of egg with folate is a viable option for supplying the general population of a food product rich in natural folates. However, attempts to increase the concentration of folate in egg beyond the achieved level of enrichment had been unsuccessful because egg folate reached a maximum plateau when folic acid (FA) was increased in the diet. Thus, experiments were conducted to determine the factors regulating the deposition of dietary FA into the eggs. In the first study, the effect of feeding equimolar intake of FA and 5-methyltetrahydrofolate (5-methylTHF), the biologically active form of folate; on egg folate concentrations, indices of folate status, and activities of folate-dependent enzymes was evaluated. Folic acid and 5-methylTHF demonstrated equivalent effects in enhancing the egg folate concentrations and improving the indices of folate status in the laying hen. The activities of folate-dependent enzymes were similar between the two forms of folate except for hepatic dihydrofolate reductase (DHFR) activity which increased in FA-fed birds compared to 5-methylTHF-fed birds. However, this demonstrated the ability of the laying hen to metabolically convert FA into its biologically active forms. Therefore, the influence of intestinal FA absorption in the regulation of FA deposition in the egg was subsequently evaluated. Using the in vitro everted intestinal sac technique, FA was absorbed in all regions of the intestine. Absorption was maximum at acidic pH 6.0, and increased in the duodenum and jejunum compared to the ileum and cecum. The rate of FA absorption in the jejunum diminished at higher FA concentrations. Therefore, further study was conducted to determine the regulation of FA absorption when levels of FA in the laying hen diet are increased. Supplementation of increased FA levels resulted to a down-regulation of FA absorption in the duodenum, but not in the jejunum of the laying hen. This down-regulation was not associated to a decreased mRNA gene expression of the duodenal folate transporters. Overall, decreased intestinal rate of FA absorption possibly associated to a post-transcriptional or translational regulation of specific folate transporters in the intestine of the laying hen may contribute to the saturation in the egg folate concentration.

We investigated the effects of dietary folic acid and age, on immunological parameters in laying hens challenged with LPS. 48 Shaver White hens at different ages were fed 2 wheat-soybean based diets with 0 or 4 mg supplemental FA per kg of diet for 8 wk. 6 hens from each dietary treatment were injected with 8 mg/kg body weight of LPS or saline and observed for 4 h. A few diet X challenge interaction were observed in young hens, whereas FA and LPS independently influenced a number of parameters. In older hens, there were very few diet X challenge interactions as well as effects of FA, whereas LPS affected several parameters. In conclusion, dietary FA influenced some immune responses in younger hens, but no such effects were observed in older hens. FA may modulate immune responses in laying hens under acute LPS challenge which could be tissue and age dependent.