عنوان مقاله [English]
Introduction Commercially available feed-grade crystalline amino acids have provided an opportunity for nutritionists to formulate low CP cost-effective diets while maintaining optimal protein utilization by birds. Lysine is the first limiting amino acid in practical diets for broilers when soybean meal is not the major protein source. Lysine supplementation under such circumstances almost becomes unavoidable in particular when dietary CP contents are to be reduced and when using the concept of ideal amino acid ratio in which lysine is used as a reference amino acid. L-Lysine HCl, which contains a minimum of 78% lysine is the dominant source of lysine for addition to poultry diets. L-Lysine sulfate products have minimum lysine contents of 46.8% in Biolys60 (Degussa AG, Frankfurt, Germany) or 51% in Lysine Plus (CJ Biotech Co. Ltd., Liaocheng, Shandong, China). A recent study reported that the bioefficacy of L-lysine sulfate relative to L-lysine HCl was similar when using daily gain and feed conversion of young pigs as the response criteria. In addition, several other swine and broiler experiments had been conducted to compare the bioefficacy of lysine in L-lysine sulfate and L-lysine HCl. Most of these studies used animal performance as the main response variable. However, very little research has been conducted to determine the effects of different lysine sources on plasma metabolites and bone characteristics of broiler chickens as the response variable. Therefore, the present study was conducted to examine the comparative effects of L-lysine sulfate and L-lysine HCl in broiler chickens using growth performance, blood metabolites and bone parameters as response variables.
Materials and Methods In this experiment compared the effects of L-Lysine-hydrochloride (Lys) and Biolys-Sulfate (BioLys) on broiler chickens’ performance and Immune Response. In a completely randomized design, 200 Ross-308 broiler chickens were allocated to 5 dietary treatments with 5 replicates and 8 birds in each. Dietary treatments including: 1- Control or basal diets (100% of supplemented Lys from Lys-HCl), 2- Ration 25:75 (75% of supplemented Lys from Lys-HCl and 25% from BioLys-Sulfate), 3- Ration 50:50 (50% of supplemented Lys from Lys-HCl and 50% from BioLys-Sulfate), 4- Ration 75:25 (25% of supplemented Lys from Lys-HCl and 75% from BioLys-Sulfate) and 5- Ration 100 (100% of supplemented Lys from BioLys-Sulfate). Feed ingredients (i.e., corn, corn gluten meal, and soybean meal) were analyzed for amino acid by NIRS in Evonik company representative in IRAN. The composition of basal diet and nutrient composition of feed ingredients. During the study, feed intake (FI) and body weight (BW) were determined at the end of starter, grower and finisher periods, and mortality-corrected FCR was calculated by accordingly. European production efficiency factor (EPEF) was calculated as: EPEF = [Viability (%) × BW (kg) / age (d) × FCR (kg feed/kg gain)] × 100.
All the birds were vaccinated intramuscularly through breast muscle with killed Newcastle disease and influenza vaccine (Cevac: New Flu-Kem) at 7 d of age, and Newcastle disease La Sota vaccine was used in the drinking water for vaccination at 14 d of age. Antibody titer against Newcastle disease, avian influenza and sheep red blood cell were detected. At the end of the experiment (42 d of age), 2 blood samples from the wing vein of 2 birds (almost near to mean body weight of each pen) were collected and blood metabolites like serum glucose, triacylglycerol, total cholesterol, albumin, uric acid and creatinine were detected. The other blood sample was used to detecting heterophil and lymphocyte percentages and heterophil to lymphocyte ratio accordingly. Finally 1 broiler from each replicate were selected and slathered, then tibia bone parameters like height, width, diameter, Ca and P percentage were detected.
Results and Discussion The results showed that from 1-42 d, broiler chickens fed the 100-diet had higher feed intake and body weight gain as compared to control group (P < 0.05). Dietary treatments had no effects on serum cholesterol, glucose and uric acid concentrations, spleen and thymus relative weight, heterophil and lymphocyte percentages and heterophil to lymphocyte ratio (H:L), antibody titter against SRBC and New-Castle diseases, tibia bone diameter and width, dry matter and ash percentages (P > 0.05). As compared to control group, broiler chickens fed diet containing 100% BioLys had higher serum total protein concentration, antibody titter against avian influenza and bone Ca and P percentages, tibia bone length, width and index (P < 0.05).
Conclusion In conclusion, inclusion of BioLys-Sulfate rather than L-Lysine-HCl to broiler chickens diet, increased broiler chickens feed intake and improved immune response and bone parameters but had no effect on broiler chickens body weight. In spite of cheaper cost of BioLys-Sulfate, its inclusion in broiler chickens diet decreased income over feed cost ratio and its use is not economically advisable.