Dietary 1,3-ß-Glucans Affect Growth, Breast Muscle Composition, Antioxidant Activity, Inflammatory Response, and Economic Efficiency in Broiler Chickens.

Recently, researchers have been intensively looking for novel, safe antibiotic alternatives because of the prevalence of many clinical and subclinical diseases affecting bird flocks and the risks of using antibiotics in subtherapeutic doses as feed additives. The present study intended to evaluate the potential use of 1,3-ß-glucans (GLC) as antibiotic alternative growth promotors and assessed the effect of their dietary inclusion on the growth performance, carcass traits, chemical composition of breast muscles, economic efficiency, blood biochemical parameters, liver histopathology, antioxidant activity, and the proinflammatory response of broiler chickens. This study used 200 three-day-old ROSS broiler chickens (50 chicks/group, 10 chicks/replicate, with an average body weight of 98.71 ± 0.17 g/chick). They were assigned to four experimental groups with four dietary levels of GLC, namely 0, 50, 100, and 150 mg kg-1, for a 35-day feeding period. Birds fed diets containing GLC showed an identical different growth rate to the control group. However, the total feed intake (TFI) increased quadratically in the GLC50 and GLC100 groups as compared to that in the control group. GLC addition had no significant effect on the weights of internal and immune organs, except for a decrease in bursal weight in the GLC150 group (p = 0.01). Dietary GLC addition increased the feed cost and total cost at 50 and 100 mg kg-1 doses. The percentages of n-3 and n-6 PUFA in the breast muscle of broiler chickens fed GLC-supplemented diets increased linearly in a dose-dependent manner (p < 0.01). The serum alanine aminotransferase (ALT) level and the uric acid level were quadratically increased in the GLC150 group. The serum levels of total antioxidant capacity, catalase, superoxide dismutase, interleukin-1ß, and interferon-gamma linearly increased, while the MDA level decreased in the GLC-fed groups in a dose-dependent manner. Normal histological characterization of different liver structures in the different groups with moderate round cells was noted as a natural immune response around the hepatic portal area. The different experimental groups showed an average percentage of positive immunostaining to the proinflammatory marker transforming growth factor-beta with an increase in the dose of GLC addition. The results suggest that GLC up to 100 mg kg-1 concentration can be used as a feed additive in the diets of broiler chickens and shows no adverse effects on their growth, dressing percentage, and internal organs. GLC addition in diets improves the antioxidant activity and immune response in birds. GLC help enrich the breast muscle with n-3 and n-6 polyunsaturated fatty acids.

Evaluation of Spray-Dried Bovine Hemoglobin Powder as a Dietary Animal Protein Source in Nile Tilapia, Oreochromis niloticus.

The present study evaluated the potential effects of dietary inclusion of spray-dried bovine hemoglobin powder (SDBH) on the growth, gene expression of peptide and amino acid transporters, insulin growth factor-1 (IGF-1) and myostatin, digestive enzymes activity, intestinal histomorphology and immune status, immune-related gene expression, and economic efficiency in Nile tilapia, Oreochromis niloticus. Two hundred twenty-five fingerlings (32.38 ± 0.05 g/fish) were distributed into five treatments with five dietary inclusion levels of SDBH: 0, 2.5, 5, 7.5, and 10% for a ten-week feeding period. Dietary inclusion of SDBH linearly increased the final body weight (FBW), total weight gain (TWG), specific growth rate (SGR), and protein efficiency ratio (PER). Additionally, a linear decrease in feed conversion ratio (FCR) and daily feed intake relative to the daily BW was reported in the highest inclusion levels (7.5 and 10%). Dietary inclusion of SDBH was associated with a significant increase in the intestinal villous height (VH), villous width (VW), villous height: crypt depth ratio (VH: CD), and muscle coat thickness (MCT), with the highest values reported in SDBH7.5 group. Increased serum growth hormone levels and decreased serum leptin hormone levels were also reported by increasing the SDBH level. The serum glucose level was decreased in the SDBH7.5 and SDBH10 groups. The digestive enzymes' activity (amylase and protease) was increased by increasing the SDBH inclusion level. An up-regulation in the expression of peptide and amino acid transporters, IGF-1, and down-regulation of myostatin was reported in the SDBH2.5 to SDBH7.5 groups. Spleen sections showed more lymphoid elements, especially in the SDBH2.5 and SDBH7.5 groups. The SDBH inclusion increased the serum lysozyme activity, nitric oxide (NO), and complement 3 (C3) levels, with the highest values recorded in the SDBH5 group. The phagocytic % and the phagocytic index were increased by increasing the SDBH inclusion %. The expressions of immune-related genes (transforming growth factor-beta (TGF-ß), Toll-like receptor 2 (TLR2), and interleukin 10 (IL10)) were up-regulated by SDBH inclusion with the highest expression in the SDBH5 group. Economically, the feed costs and feed costs/kg gain were linearly decreased in the SDBH7.5 and SDBH10 diets. In conclusion, spray-dried bovine hemoglobin powder could be used as a protein source for up to 10% of the diets of Nile tilapia for better growth and immune status of fish.