Disinhibition of antibiotics promotes the use of probiotics, prebiotics, immune enhancers, and plant extracts. We investigated the effects of stevioside on growth performance, nutrient digestibility, serum parameters, and intestinal microflora in broilers. Eight hundred ninety-six one-day-old male Arbor Acres broiler chicks (average body weight 48.36 ± 0.21 g) were allotted to 1 of 7 experimental treatments. Treatments consisted of: (1) control (basal diet without supplemental stevioside), (2) 100 mg kg⁻¹ supplemental stevioside (S100), (3) 200 mg kg⁻¹ supplemental stevioside (S200), (4) 400 mg kg⁻¹ supplemental stevioside (S400), (5) 800 mg kg⁻¹ supplemental stevioside (S800), (6) 1600 mg kg⁻¹ supplemental stevioside (S1600), and (7) 3200 mg kg⁻¹ supplemental stevioside (S3200). Performance was not affected by stevioside concentration. Dietary stevioside supplementation increased the digestibility of calcium (P < 0.05) and tended to improve phosphorus digestibility (P = 0.0730). There was a linear effect of dietary stevioside on the concentration of serum glucose (P < 0.05). The serum IgG and IgA levels were linearly increased by stevioside supplementation (P < 0.05). In the ileal digesta, the concentration of E. coli decreased with increasing dietary stevioside supplementation (P < 0.05). On the contrary, dietary stevioside supplementation increased the concentration of Bifidobacteria (P < 0.01) and tended to improve the concentration of Lactobacillus (P = 0.0791). In conclusion, our data suggest that stevioside supplementation could improve the calcium and phosphorus digestibility and decrease blood glucose levels of broilers. Additionally, dietary stevioside supplementation significantly increased Bifidobacteria in the cecal digesta, and decreased E. coli.

Objective: Astaxanthin is a natural super antioxidant. The present study was carried out to investigate the effect of astaxanthin rich Phaffia rhodozyma (PR) supplementation in diets on laying production performance, egg quality, antioxidant defenses and immune defenses in laying hens.Methods: A total of five hundred and twelve 60-week-old Lohmann Brown laying hens (2,243±12 g) were randomly assigned to four groups, each including 4 replicates with 32 birds per replicate. Astaxanthin rich PR was added to corn-soybean meal diets to produce experimental diets containing 0 (Control), 800 mg/kg, 1,200 mg/kg, and 1,600 mg/kg PR, respectively. The astaxanthin content in the diet was 0.96 mg/kg, 1.44 mg/kg and 1.92 mg/kg respectively.Results: Results showed that dietary PR supplementation tended to increase daily feed intake (p = 0.0512). There was no effect of astaxanthin rich PR on Haugh units, albumen height, egg shape index, eggshell strength, and eggshell thickness at weeks 6 (p>0.05). However, egg yolk color was significantly improved (p<0.05). In addition, astaxanthin rich PR supplementation significantly increased serum glutathione peroxidase and superoxide dismutase activity (p<0.05), increased serum immunoglobulin G content (p<0.05), and reduced malondialdehyde content (p<0.05) in laying hens.Conclusion: In conclusion, astaxanthin rich PR can improve the color of egg yolk, enhance the antioxidant defenses, and regulate the immune function.

Copper bioavailability, mineral utilization, and lipid metabolism in broilers | Aiyou Wen, Sifa Dai, Xuezhuang Wu, Zhihua Cai | Agricultural Journals

Objective: The aim of this study was to evaluate the effect of pre-slaughter fasting time on carcass yield, meat quality, blood parameters and glucose metabolism in broilers.Methods: Four hundred and fifty Arbor Acres (AA) broilers at 42 days of age were divided into 5 groups with 6 replicates in each group and 15 chickens as one replicate. Following this period, broilers from each group were distributed among five groups according to preslaughter fasting period as 4, 8, 12, 16, or 20 h.Results: With increasing fasting time, the carcass yield (p<0.01), the breast muscles yield (p<0.01) and the thigh yield (p<0.01) of the broilers were all linearly increased. With increasing fasting time, the L* values (p<0.01), cooking loss (p = 0.020), moisture content (p<0.01) in the leg muscles linearly downregulated, while the drip loss (p = 0.043), pH45 min (p<0.01) and pH24 h (p0.10), while the increase of fasting time resulted in a linear decrease of the blood glucose (p = 0.021) and, more specifically, the glycogen content of the liver and leg muscles (p<0.001). With increasing fasting time, the aspartate transaminase (p<0.01), uric acid (p<0.01), and triglycerides (p<0.01) in serum linearly downregulated, while the alanine aminotransferase was linearly upregulated.Conclusion: The results of this study show a significant influence of fasting time on carcass yield and meat quality in broilers. Moderate fasting (8 to 12 h) before slaughter can reduce the weight loss of broilers. Prolonged fasting (≥16 h) increased body weight loss, decreased slaughtering performance and fluctuating blood indexes of broilers.