Effects of embryonic day and in ovo feeding of β‑hydroxy-β-methylbutyrate on hatching performance, organ development, and jejunal morphology in Japanese quail.

The objective of this study was to investigate the effects of embryonic day and in ovo feeding of β‑hydroxy-β-methylbutyrate (HMB) on hatching performance, organ development, and jejunal morphology in Japanese quail. A total of 520 fertile eggs were assigned to a 2 × 2 factorial arrangement with two embryonic days of in ovo feeding, embryonic day 7 (E7) and embryonic day 11 (E11), and two in ovo feeding treatments, 1× PBS and 1% HMB. Each treatment included 10 replicates with 13 eggs per replicate, and 0.05 mL of the assigned solution was injected into the air cell. The results indicated a significant interaction (P < 0.05) between the embryonic day of in ovo feeding and in ovo feeding treatment for hatching performance and hatchability. On E7, the HMB group showed greater (P < 0.05) body weight (BW) and chick yield, and a shorter (P < 0.05) hatch window than the PBS group. On E11, the HMB group showed decreased (P < 0.05) post-pipping mortality compared to the PBS group. Regarding the main effect of the embryonic day of in ovo feeding, the E11 groups showed increased (P < 0.05) relative liver and intestinal weights compared to the E7 groups. Regarding the main effect of in ovo feeding treatment, in ovo feeding of HMB increased (P < 0.05) hatch of set, hatch of fertile, BW, chick yield, radius, villus height, villus width, and villus height-to-crypt depth ratio compared with in ovo feeding of PBS. In ovo feeding of HMB decreased (P < 0.05) the hatch window and late embryo mortality compared with in ovo feeding with PBS. In conclusion, in ovo feeding of HMB may improve hatching performance, reduce late embryonic mortality, and support jejunal development in Japanese quail, with responses partly depending on the embryonic day of administration.