The work focused on the study of the immunomodulatory and gut-protecting effect of humic substances (HS) in broilers. The diet of experimental chicks was enriched with 0.8% of HS. We noted that HS had a stimulatory effect on the phagocytic activity and the engulfing capacity of phagocytes, however, the level of oxidative burst of phagocytes was not affected. We observed a significant increase of CD4+: CD8+ lymphocyte ratio, an indicator of immune stimulation. HS did not influence the IgA gene expression. In contrast, we observed a significant increase in the expression of MUC-2 (intestinal mucin 2) gene, and a decrease in the expression of IGF-2 (insulin-like growth factor 2) and also AvBD2 (avian beta defensin 2) genes. A decreased Enterobacteriaceae counts in the gut of experimental animals showed a positive effect on intestinal microbiota. We confirmed a gut-protecting and an immunostimulatory effect of HS in broiler chickens.

This study was conducted to evaluate the effect of dietary supplementation with Spirulina platensis (SP) on the productive performance, carcass characteristics, behavior, blood serum metabolites, hematological indices, and economic efficiency of Fayoumi broiler chickens for a 56-day. In total, 120 one-day-old broiler chicks were randomly distributed among four dietary treatments with three replicates (n = 10/group) for 8 weeks. The dietary treatments were a control basal diet without SP and the same basal diets supplemented with 0.25, 0.5, or 1.0% SP. Birds fed 1% Spirulina-supplemented diets recorded significantly (p < 0.05) higher body weight, weight gain, and feed conversion ratio and less overall feed intake and feeding behavior than those in the control group. No significant changes (p > 0.05) were recorded in the dressing percentage or the relative weights of internal organs among the different experimental groups, except for the thymus. Diets containing 0.5 or 1.0% SP saw an increase (p < 0.05) in serum total protein and globulin and a reduction (p < 0.05) in serum cholesterol concentration. The lymphocyte percentage in birds fed SP diets was significantly (p < 0.05) higher than in birds fed the control diet. These results suggest that adding SP up to 1% to the broiler diets could positively affect some important blood biochemical parameters, enhance their immunity response, and improve their growth performance. However, from an economic point of view, supplementation with 0.25% of SP is recommended for Fayoumi broiler chickens.

Public concern over drug resistance has led to governmental regulations banning the use of antibiotics as growth promoters, stimulating interest in developing complementary strategies to maintain animal production, mitigate infections, and enhance muscle characteristics and quality parameters, especially in meat-producing animals. Probiotics are recognized as a potential strategy for improving growth, primarily by promoting intestinal homeostasis. These microorganisms are suggested to modulate gut microbiota, preserving their ecosystem and influencing secondary metabolite production, which can directly or indirectly regulate skeletal muscle metabolism by influencing the expression of key muscle-related genes and the activity of various signaling factors. Several studies have documented the potential benefits of various strains of Bacillus, Enterococcus, and members of the Lactobacillaceae family on muscle characteristics. These studies have shown that probiotics not only modulated myogenic factors but also influenced proteins and enzymes involved in signaling pathways related to carbon metabolism, inflammatory response, mitochondrial dynamics, and antioxidant activity. These effects have been associated with improvements in meat quality parameters and enhanced growth performance. This manuscript seeks to present a brief overview of the impact of probiotic supplementation on muscle health and the quality of meat in broiler chickens.

Gamma-linolenic acid (GLA) is a fatty acid from the ω-6 family. It is able to deliver a wide range of health benefits arising from its anti-inflammat