Our trial was conducted to study the effects of formic acid (FA) and potassium di-formate (KDF) in broiler ration on performance, carcass traits, blood biochemical, intestinal microbial load, histological picture of intestine and immune parameters of broilers. In this study 360 one-day-old broiler chicks were divided to 3 groups with 3 replicates of 40 chicks each. The trial continued for 35 days. The control group was fed only basal diet (G1). Group 2 (G2) were fed basal diet supplemented with FA (5 g/kg diet), and group 3 (G3) received basal diet supplemented with KDF (5 g/kg diet). The results showed that both FA and KDF significantly increased body weight gain (BWG), dressing percentage of broilers and significantly decreased feed conversion ratio (FCR) (P < 0.05). The highest percent of breast and thigh was observed in G3. The improvement in villus height was observed in G2 and G3 compared with the control one, and the highest was in G3. The results evidence that the using of FA or KDF in broiler feeds have significant effects on performance, immune parameters, and gut health without having any significant effects on blood biochemical. However, KDF is more effective than FA as little amount of FA reaches the small intestine due to metabolism and absorption, whereas KDF permits a proportion of FA to pass through the fore-gut intact and enter the small intestinal tract. In addition, FA has a strong odor and corrosiveness to gastrointestinal tract which limits its use.

The present study aimed to evaluate the effect of dietary fermented extracts sourced from Saccharomyces cerevisiae (nucleotides, β-glucans and MOS) (Hilyses^®) on the production and health of Nile tilapia (Oreochromis niloticus) broodstock, as well as on seed survival and performance. The trial was performed in a hatchery along the spawning season and continued in the laboratory to monitor the performance in fry and fingerlings. The broodstock were divided into two groups, (C) fed a basal diet and (H) fed 0.4% Hilyses. Blood and histological parameters, antioxidant power, cortisol level and the expression of some immune-related (TLR-2, IL-1β and TNF-α) and growth-related genes (MUC-2 and IGF-1) were measured. The obtained seeds were subdivided into four treatments: (C-C) fed a basal diet, (C-H) fed 0.4% Hilyses, (H-C) fed a basal diet and (H-H) fed 0.4% Hilyses. Results revealed that the dietary inclusion of Hilyses in the broodstock increased seed production, survival, hematological parameters, and antioxidant power. Moreover, it improved the intestinal microstructure and upregulated the immune- and growth-related genes. The growth indices of fry and fingerlings were significantly increased in all Hilyses-treated groups (p < 0.05). The performance in the (H-H) group significantly surpassed those of all groups. Therefore, dietary fermented yeast could be used as a strategic solution to sustain tilapia production.