Comparison of performance and feed digestibility of the non-antibiotic feed supplement (Novacid) and an antibiotic growth promoter in broiler chickens.

Antibiotic growth promoters have been widely used in poultry to improve overall performance. The emergence of antibiotic resistance has resulted in sanctions imposed on the use of antibiotics in poultry diets, and alternatives such as herbal extracts are being considered to improve growth performance. The aim of this study was to compare the performance and feed digestibility of the feed supplement Novacid, which contains organic acids, glucomannan, and phytochemicals, with that of the antibiotic growth promoter bacitracin methylene disalicylate (BMD) in commercial broiler chickens. Six hundred 1-d-old Ross × Ross 308 male broiler chicks were randomly and equally assigned to six treatment groups with five replicates each (20 chicks per replicate). The chicks were fed a corn-soybean meal basal diet, and divided into two groups: unchallenged and challenged with E. coli (400 mg/kg Escherichia coli inoculation). Each of these groups was divided into three study groups: untreated, treated with 0.05% Novacid, and treated with 400 mg/kg BMD. At day 42, inclusion of Novacid or BMD significantly (P < 0.05) improved the performance in the unchallenged groups relative to the control group. However, in E. coli-challenged groups, Novacid and BMD did not improve performance. Ileal digestibility of crude fat, crude protein, and gross energy were reduced in the Novacid group (P < 0.05). BMD and Novacid were equally effective in controlling ileal nutrient digestibility and feed coliform count (P < 0.05). Novacid reduced cecal E. coli and Salmonella count compared to BMD and control. Thus, a phytochemical feed supplement with organic acids and glucomannan could be an effective substitute for antibiotic growth promoters in broiler diets, but cannot replace antibiotics to counter potent infectious agents such as E. coli.

Effects of Xylanase Supplementation and Citric Acid on Performance, Ileal Nutrients Digestibility, and Gene Expression of Intestinal Nutrient Transporters in Broilers Challenged with Clostridium perfringens.

This study was conducted to evaluate the effects of xylanase and citric acid (CA) on growth, digesta pH, ileal populations of Clostridium perfringens and lactic acid bacteria, ileal nutrient digestibility, digestive enzyme activity, and mRNA expression of intestinal nutrient transporters in starter broilers challenged with C. perfringens. The experiment was conducted in a 2×2 factorial arrangement with two levels of CA (0 and 30 g/kg) and 2 levels of xylanase (0 and 200 mg/kg). Each of the four dietary treatments was fed to six replicate pens (15 birds/pen) between 0 and 21 d of age. Dietary CA significantly increased ADFI and ADG; meanwhile, xylanase addition led to a substantial reduction in FCR (P<0.05). No differences in digesta pH, C. perfringens counts, or quantity of lactic acid bacteria were found between the treatments. Xylanase supplementation increased AME values (P<0.01) and ileal digestibility of CP (P<0.05) in challenged birds. The inclusion of CA also increased the AME (P<0.01), and tended to increased ileal CP digestibility (P=0.085). Xylanase supplementation increased α-amylase, trypsin, and sucrose activity in the jejunum (P<0.01). Dietary CA significantly increased (P<0.01) villi length as well as the villus length to crypt depth ratio in jejunum segments. The jejunal mRNA expression of sodium glucose co-transporter 1 (SGLT1) and H+-dependent peptide transporter 1 (PepT1) were upregulated by xylanase supplementation (P<0.01). The results suggest that dietary CA can promote growth as well as improve intestinal morphology and AME in birds challenged with necrotic enteritis. This study shows that xylanase supplementation improved FCR and AME in birds independent of C. perfringens infection; it also elevated the apparent ileal digestibility of CP, digestive enzyme activities, and mRNA expression of nutrient transporters in challenged birds.

Simple cannulation procedure for serial blood sampling through cutaneous ulnar vein in chickens.

The objective of the study was to collect repeated, low-stress blood samples from the ulnar vein of chickens required for pharmacokinetic studies or hormonal assays. The study used 5 apparently healthy, unsexed, commercial broiler chickens about 6 weeks old and weighing 1.7-1.9 kg for serial sampling of blood. The study prepared the birds prior to cannulation and penetrated the catheter through the skin and into the lumen of the ulnar vein. The study successfully carried out serial blood samplings in 4 of 5 cannulated birds. Heparin (10%) solution maintained patency and prevented blood clot formation inside the cannula. However, the study found repeated clotting occurring in 1 bird. Cannula failed to maintain patency; the study could not carry out blood sampling properly, which was attributed to air embolism that might have occurred during catheter manipulation or repeated filling of cannula with heparin solution. The study observed no hematoma or inflammation at the site of cannulation. Owing to the advantages and to facilitate compliance with nonhuman animal welfare, this technique seems simple and efficient, allowing adoption for serial blood collection in chickens.