Effects of Dietary Valine Levels on Production Performance, Egg Quality, Antioxidant Capacity, Immunity, and Intestinal Amino Acid Absorption of Laying Hens during the Peak Lay Period

Abstract

The present study aimed to assess the impact of dietary valine levels on layer production performance, egg quality, immunity, and intestinal amino acid absorption of laying hens during the peak lay period. For this purpose, a total of 960 33-week-old Fengda No.1 laying hens were randomly divided into five experimental groups and fed with valine at the following different levels in a feeding trial that lasted 8 weeks: 0.59, 0.64, 0.69, 0.74, and 0.79%, respectively. Productive performances were recorded throughout the whole rearing cycle and the egg quality, serum indexes, and small intestine transporters expression were assessed at the end of the experiment after slaughter (41 weeks) on 12 hens per group. Statistical analysis was conducted by one-way ANOVA followed by LSD multiple comparison tests with SPSS 20.0 (SPSS, Chicago, IL, USA). The linear and quadratic effects were tested by SPSS 20.0. Egg mass, laying rate, broken egg rate, and feed conversion ratio were significantly improved with increasing dietary valine levels. However, the egg weight, eggshell thickness, albumen height, Haugh unit, and egg yolk color were significantly decreased with increasing dietary valine levels. Serum catalase (CAT), immunoglobulin A (IgA) and IgM levels, and malondialdehyde (MDA) levels were negative responses to valine-treated laying hens. Dietary supplemented valine enhanced the trypsin activity of duodenum chime and promoted the mRNA expression levels of ATB0,+, and LAT4 in the jejunum and corresponding serum free Ile, Lys, Phe, Val, and Tyr level. However, valine treatment significantly downregulated the mRNA expression levels of PePT1, B0AT1, LAT1, and SNAT2 in the small intestines and corresponding serum free Arg, His, Met, Thr, Ala, Asp, Glu, Gly, and Ser level. Our results suggest that 0.79% valine dietary supplementation can improve production performance by promoting amino acid nutrient uptake and utilization, and suggest a supplement of 0.79% valine to diet.

Dietary Valine Ameliorated Gut Health and Accelerated the Development of Nonalcoholic Fatty Liver Disease of Laying Hens

“…In addition, isobutyric and isovaleric acids, generated by fermentation of BCAAs, have been confirmed that could inhibit both cAMP-mediated lipolysis and insulin-stimulated de novo lipogenesis in primary rats and human adipocytes [ 19 ]. Our recent research found that diet supplemented with valine promoted amino acid nutrient uptake and utilization by upregulating mRNA expression levels of amino acid transporters in the jejunum and corresponding serum free amino acids concentrations, ultimately improving the production performance of laying hens [ 20 ]. Nevertheless, the effects of dietary valine supplementation on the gut microbiota, intestinal barrier function, and lipid metabolism in the liver of laying hens during the peak laying period have not been fully understood.…”

Effects of L-valine in layer diets containing 0.72% isoleucine

“…Results from Jian et al (2021) revealed a significant quadratic decrease in serum IgA and IgM with increasing valine (0.59, 0.64, 0.69, 0.74, and 0.79%) in diets of 33- to 40- week-old Fengda No.1 laying hens. Serum IgM levels did not change among diets [ 34 ]. Investigators (Azzam et al, 2015) reported that high levels of valine did not negatively affect the immune function in layers [ 2 ].…”

Functional role of branched chain amino acids in poultry: a review

“…(2018) estimated that the efficiency of valine and isoleucine utilization by 30-wk-old broiler breeders to be 0.70 and 0.66%, respectively, where the daily intake was estimated to be 803 mg/d for valine and 708 mg/d for isoleucine using a broken line model. In a recent laying hen trial from 33 to 41 wk, valine was added at different levels from 0.59 to 0.79% where the feed intake was around 100 g/d/bird ( Jian et al., 2021a ). The authors reported that the egg mass, laying rate, and trypsin activity in the duodenum, and AA transporter gene expression levels were increased with increasing valine, whereas the Haugh unit, eggshell thickness, egg yolk color, and immune parameters decreased.…”