Effects of In Ovo Injection of Different Gut Health-Promoting Additives on Hatchability, Liveability and Intestinal Total Aerobic Bacterial Load in Broiler Chickens

This study evaluated the effects of the in ovo injection of a prebiotic, a probiotic and a postbiotic on hatchability, livability, early growth performance and intestinal total aerobic bacterial load in broiler chickens. A total of 300 fertile Ross 308 eggs obtained from a 32-week-old breeder flock were individually weighed, allocated to five equal groups (n = 60 eggs per group) and incubated under standard conditions. At 17.5 days of incubation, 0.2 mL of the corresponding solution was injected into the amniotic fluid: negative control (no injection), positive control (sterile distilled water), prebiotic (0.2% inulin), probiotic (0.2% Bacillus clausii) and postbiotic (0.2% Lactiplantibacillus plantarum-derived preparation). After hatching, the chicks were reared for 10 days in five replicate pens per group and were offered a commercial starter diet and water ad libitum. Hatchability, livability, body weight, body weight gain, feed intake and feed conversion ratio were recorded, and the intestinal contents of six chicks per group were cultured to determine total aerobic bacterial counts (log10 cfu/g). Hatchability ranged from 90.0% to 95.0% and livability from 94.4% to 100.0%, with no difference among groups (χ² = 1.77, P = 0.779 and χ² = 6.76, P = 0.149, respectively). Body weight at hatch and at 10 days, body weight gain, feed intake and feed conversion ratio were also similar among groups (P > 0.05), although the highest body weight gain was numerically recorded in the prebiotic group. Total aerobic bacterial counts did not differ significantly (P = 0.101); the lowest mean was obtained in the probiotic group (6.16 log10 cfu/g) and the highest in the prebiotic group (6.90 log10 cfu/g). Under the present conditions, the in ovo delivery of these three biotics neither impaired nor improved hatching results, early performance or intestinal aerobic load.