Effect of Supplementing Synthetic Amino Acids in Low-protein Diet and Subsequent Re-feeding on Growth Performance, Serum Lipid Profile and Chemical Body Composition of Broiler Chickens

Abstract

This study was conducted to evaluate the effects of supplementing methionine (Met) and lysine (Lys) in low protein (Low-CP) diet during 1-21 days of age, and subsequent re-feeding with conventional diet during 22-42 days of age on growth performance, serum lipid profile, chemical body composition and carcass quality of broiler chickens. During 1-21 days of age (starter period), 480 male broiler chicks (Ross 308) were divided into three treatments and given the following diets: 1) conventional diet group (all nutrients met the requirements of the strain), 2) Low-CP diet without Met and Lys supplementation and 3) the Low-CP diet supplemented with Met and Lys (Low-CP + Met + Lys). During the finisher period (22-42 days of age), all groups were fed a diet containing the same nutrients in accordance with the recommendations of the strain. At 21 days of age, Low-CP + Met + Lys diet showed significantly better growth performance and breast meat yields than those of the Low-CP diet group. Feed and protein intake of the chicks fed conventional diet was significantly higher than both of the other groups (P＜0.01), whereas Low-CP + Met + Lys diet clearly improved protein efficiency (P＜0.01). Feeding Low-CP diet increased abdominal fat content and body energy content (P＜0.05), while the supplementing synthetic amino acids slightly decreased the fat content. Triglyceride, very low density lipoprotein (VLDL) and T3 hormone in blood were significantly increased in Low-CP + Met + Lys diet group compared to the conventional diet (P＜0.05). After the re-feeding phase, feeding Low-CP diet groups were unable to compensate body weight equal to the conventional diet, although a compensation of FCR was observed. Feeding Low-CP + Met + Lys diet showed the same breast meat yield compared to the conventional diet, but abdominal fat, triglyceride and VLDL in blood were significantly increased (p＜0.05). In conclusion, supplementing Met + Lys in Low-CP diet improved performance production, but was still inferior to the conventional diet.

Chronic feeding with protein-restricted diets affect ileal amino acid digestibility and the expression of nutrient-sensing, hormone secretion, gastrointestinal digestive enzyme, and nutrient transporter genes in young weaned pigs

“…This could be supported by the increasing trend in serum cholesterol and triglyceride levels observed in our study in pigs receiving the protein-restricted diets similar results have been reported elsewhere [35,[40][41][42][43][44]. Subsequent experiments also confirmed that an excessively CP-restricted diet and serious AA imbalance lead to a decrease in protein synthesis, with the remaining energy being transferred to fat deposition in broiler chickens and pigs [35,45,46].…”

Supplementation of a low-protein diet with tryptophan, threonine, and valine and its impact on growth performance, blood biochemical constituents, immune parameters, and carcass traits in broiler chickens

“…Lower serum total triglycerides in broiler chickens fed the CP-2% diet were observed. As FI of the low-CP diet group (CP-2%) was low, broiler chickens may have the ability to utilize body fat as an energy supply to compensate their feed efficiency [ 40 ], and thus resulted in low serum triglycerides. Creatine and uric acid serum levels are good indicators of protein and AA metabolism [ 41 ].…”

Untitled

“…Hence, only a part of the food supply will heat up the broiler house. Extensive work has been done to estimate the efficiency of the breeding and as a side effect, estimates on animal emissions are available (Nukreaw and Bunchasak 2015). However, these estimates are only mean values, whereas it is to expect that the animal emissions vary with time (Pedersen and Sällvik 2002).…”

“…As has been stated, the values obtained through food supply do not have a good temporal resolution. For their calculation values from Nukreaw and Bunchasak (2015) have been used. With the help of this graph, the value for in (29) could be chosen to 0.8 for the broiler house in consideration, this value gave the best match between the average emissions measured through the ventilation and those calculated through food supply.…”