Effect of Methionine Deficiency on the Growth Performance, Serum Amino Acids Concentrations, Gut Microbiota and Subsequent Laying Performance of Layer Chicks

Abstract

This study was conducted to investigate the effect of methionine (Met) deficiency in the rearing period on the growth performance, amino acids metabolism, intestinal development and gut microbiome of egg-laying chicks and the continuous effects on the performance, egg quality, and serum amino acids metabolism of the subsequent development process. Three hundred sixty one-day-old chicks were randomly divided into two groups and fed on a basal diet (NC group, Met 0.46%) and Met deficiency diet (Met- group, Met 0.27%). Each group included six replicates with 30 chicks per replicate. The trial lasted 6 weeks (0-6 weeks), both groups were fed the same basal diet which met the needs of Met during the observation period (7-24 weeks). Results showed that Met deficiency significantly decreased (P < 0.05) body weight (BW), average daily weight gain (ADG), average daily feed intake (ADFI) and tibia length (TL) compared to the NC group during the trial period (0-6 weeks). Also, Met deficiency dramatically increased (P < 0.05) feed conversion ratio (FCR) during the trial and observation period (7-24 weeks). In addition, during the observation period, the BW and ADG were decreased (P < 0.05) in the Met- group. Moreover, Met- group decreased (P < 0.05) villi height and villi height/crypt depth ratio in jejunum at 6th weeks. In addition, the concentrations of serum main free amino acids (FAA) in the Met- group were significantly increased (P < 0.05) at 6th weeks, while were decreased at 16th weeks. Based on the α-diversity and PCoA analysis in β-diversity, there were no significant differences in the cecal microbial composition between NC and Met- groups. However, the LEfSe analysis revealed that differential genera were enriched in the NC or Met- groups. The Haugh unit, shell thickness and egg production in the Met- group were significantly lower (P < 0.05) than in the NC group. In conclusion, these results revealed that dietary supplementation of appropriate Met could substantially improve the growth performance, host amino acid metabolism and intestinal development and continuously improve the laying performance and thus boost the health of growing hens.

Keywords: amino acid; egg-laying chicks; growth performance; intestinal development; methionine deficiency.

Figure 1

Effects of Met deficiency in rearing period diets on small intestine morphologic structure of egg-laying chicks. (A) Representative samples from histological stained sections showed Met- group had lower jejunal villus height and deeper ileal crypt depth. (B) Villus height of duodenum, jejunum, and ileum. (C) Crypt depth of duodenum, jejunum, and ileum. (D) Villus height-to-crypt depth ratio (V/C) of duodenum, jejunum, and ileum. Data were presented as means ± SEM. Significant differences were tested by student's t-test. *Indicates significant difference, P < 0.05; ***, P < 0.001.

Figure 2

Effects of Met deficiency in rearing period diets on serum concentration of amino acids (AA) of laying hens. (A–D) serum concentration of amino acids (AA) of laying hens at 6th weeks, (A) Nonpolar R-side Amino acids. (B) Uncharged polar R-side Amino acids. (C) Positively charged R-side Amino acids. (D) Negatively charged R-side Amino acids. (E–H) serum concentration of amino acids (AA) of laying hens at 16th weeks. (E) Nonpolar R-side Amino acids. (F) Uncharged polar R-side Amino acids. (G) Positively charged R-side Amino acids. (H) Negatively charged R-side Amino acids. (I–L) serum concentration of amino acids (AA) of laying hens at 24th weeks. (I) Nonpolar R-side Amino acids. (J) Uncharged polar R-side Amino acids. (K) Positively charged R-side Amino acids. (L) Negatively charged R-side Amino acids. Data were presented as means ± SEM. Significant differences were tested by student's t-test. *Indicates significant difference, P < 0.05; **, P < 0.01.

Figure 3

Effects of Met deficiency in rearing period diets on the gut microbiota of egg-laying chicks at 6 weeks. (A) Venn diagram of the shared and total operational taxonomic units (OTUs) in the NC and Met- groups. (B) The principal coordinate analysis (PCoA) (Bray-Curtis distance) plot of the gut microbial community structure between the NC and Met- group. (C) Relative abundance of gut microbiota at the phylum level. (D) Relative abundance of gut microbiota at the genus level. (E) Histograms of the linear discriminate analysis (LDA) score (threshold ≥ 2) in Met- and NC groups are plotted. Linear discriminate analysis effect size (LEfSe) was performed to determine the difference in abundance.