RESPONSE OF GUINEA FOWL (Numida meleagris) TO IN OVO INJE

Abstract

ABSTRACT In ovotechnique is an emerging tool in poultry production that enables the direct delivery of nutrients and bioactive compounds to the developing embryo, potentially improving post-hatch performance and physiological outcomes. This study investigated the effects of in ovo administration of vitamin B6 (pyridoxine) at different embryonic stages on hatchability, haematology, gut development, and growth in guinea fowl (Numida meleagris). A total of 160 guinea fowl eggs were sourced from a reputable breeder, of which 152 were settable and incubated under standard conditions. On day 21 of incubation, fertility was assessed by candling, and 112 fertile eggs (73.68%) were identified and evenly distributed into four treatment groups (28 eggs per group): a non-injected control and three groups injected with 0.05 mL of pyridoxine solution (100 µg/mL) into the amnion on embryonic days 21, 23, and 25, respectively. At hatch (day 28), 80 keets were allocated into replicates based on number of hatched keets per treatment, and a post-hatch study was conducted over a 10-week period. Data collected were subjected to Analysis of Variance in a Completely Randomised design, utilizing Minitab® 21.4.1 (Minitab, 2023). The results showed that hatchability was significantly (p < 0.05) affected by the timing of injection; both the control (93.30%) and day 25 group (85.71%) maintained significantly higher hatchability percentage compared to day 21 (57.14%) and day 23 (46.43%) groups. At 7 days old, monocyte of keets from eggs in day 21 group were significantly reduced, while at day 70 days old, red blood cell (RBC) counts were significantly higher in birds from the day 25 group. Keets from eggs injected on day 21 exhibited the highest albumin-to-globulin (A/G) ratio and cholesterol levels, while significantly lower cholesterol concentrations were observed in those injected on days 23 and 25 relative to the control. Moreover, antioxidant enzymes activities specifically glutathione peroxidase (GPx), superoxide dismutase (SOD) with catalase (CAT), and were highest in keets from eggs in day 23 group. Significantly higher liver and jejunal weights, was also observed in keets from eggs in day 25 group, whereas those from the day 21 group recorded the highest caecal weight. In conclusion, administering vitamin B6 in ovo on day 25 of embryonic development did not have adverse effect on hatchability percentage, while enhancing haematological indices and early gut development. Additionally, in ovoinjection on day 23 is considered beneficial for improving serum cholesterol, antioxidation and intestinal muscle structure in guinea fowl.