Effects of in ovo injection of lysine and methionine into fertile broiler (parent stock) eggs on hatchability, growth performance, caecum microbiota, and ileum histomorphology

Abstract

We investigated the effect of in ovo injection of lysine, methionine, or their mixture into fertile broiler eggs on hatchability, chick weight, growth performance, inner organ development, caecum total aerobic bacteria, E. coli, coliforms, Enterobactericaea, and ileal histomorphology of broilers. Three hundred fertile eggs obtained from 60-week-old Ross 308 broiler breeders were used. Before this study, a preliminary study was conducted to determine the optimal amino acid dose. Optimum amino acid dose was determined as 2 mg/0.2 mL. Before replacing hatching machine, eggs were weighed individually and numbered. On day 16 of incubation, these eggs were allocated to treatment groups: negative control (no injection), positive control (distilled water injection 0.2 mL), lysine (2 mg/0.2 mL), methionine (2 mg/0.2 mL), and lysine + methionine (1 + 1 mg/0.2 mL). The hatching window lasted 32 h. During hatching, chicks hatched in the first hour and the last 6 h were discarded from the study to ensure equal hatching time. After hatching, 120 one-day-old healthy chicks were divided into five treatment groups with three replicates, each including eight birds, for 21 days. These chicks were given a starter diet (3080 kcal/kg metabolizable energy and 22% crude protein) during the trial. The results showed that in ovo injection of lysine, methionine, and lysine + methionine did not affect relative chick weight, livability, growth performance, caecum microbiota, and ileal villi length and thickness. Lysine injection increased hatchability compared with the negative control and methionine-injected groups. Gastrointestinal weight increased in lysine-injected group compared with the negative control group. The in ovo injection of 2 mg/0.2 mL lysine have a positive effect on the hatchability of fertile eggs.