Effect of different dietary protein levels and amino acids supplementation patterns on growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs

Abstract

Background This study was conducted to determine the effects of different dietary protein levels and amino acids supplementation patterns in low protein diets on the growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs. Forty-two barrows (25.00 ± 0.39 kg) were randomly assigned to 7 diets. Diet 1: the high crude protein diet with balanced for 10 essential amino acids (EAAs). Diet 2: the medium crude protein diet with 2% (approx) decreased protein level of Diet 1 and balanced 10 EAAs. Diet 3: the low crude protein diet with 4% decreased protein level of Diet 1 and balanced 10 EAAs. The protein levels of Diet 4, 5, 6 and 7 were the same as that of Diet 3. Diet 4 was only balanced for lysine (Lys), methionine (Met), threonine (Thr) and tryptophan (Trp); Diet 5 and 6 were further supplemented with extra isoleucine (Ile) or valine (Val), respectively; Diet 7 was further supplemented with extra Ile + Val. Results Over the 112 days trial, the reduction of dietary protein by 2% or 4% with balanced10 EAAs significantly decreased nitrogen excretion (P < 0.05), but had no effects on growth performance and carcass characteristics (P > 0.05). In low protein diet, Val supplementation significantly increased body weight gain at 25–50 kg phase (P < 0.05), while Ile supplementation at 75–100 kg phase and 100–125 kg phase significantly reduced the ratio of feed to gain (P < 0.05). No effect of different dietary protein levels and amino acids supplementation patterns in low protein diets on carcass characteristics was observed (P > 0.05). The total N excretion of pigs supplemented with only Lys, Met, Thr and Trp was numerically higher than that of pigs fed with extra Ile, or Val, or Ile + Val diets. Conclusion In low protein diet, Val is more required than Ile in the early growing phage (25–50 kg), while Ile becomes more required in the late growing and finishing phage (75–125 kg).

Effect of low protein diets added with protease on growth performance, nutrient digestibility of weaned piglets and growing-finishing pigs

“…Diets designed to reduce pigs’ nitrogen excretion will only be acceptable to the pig industry if they can maintain pig performance [ 16 ]. In this study, the effects of LP and HP diets on growth performance showed no significant difference throughout the experiment, similar to findings of previous studies [ 17 , 18 ]. Over the past 10 years, the genetic potential of pigs has been improved dramatically, very different from rates of growth and protein deposition in pigs in experiments used to create NRC [ 13 ] requirements.…”

Effects of Intensive Fattening With Total Mixed Rations on Carcass Characteristics, Meat Quality, and Meat Chemical Composition of Yak and Mechanism Based on Serum and Transcriptomic Profiles

“…The tenderness was mainly determined by the content and distribution of connective tissue in the meat, the diameter of muscle fibers, sarcoplasmic protein content, and intramuscular fat content in the meat (17). The long-term grazing and raising of yaks and the aging of slaughtering lead to a poor tenderness of yak meat, which restricts its market acceptance (21). Many studies have shown that fattening can increase the intramuscular fat content in LD of yak, reduce shear force, and improve meat quality (2).…”

“…The nutritional level of TMR is much higher than the forage. It was reported that a high protein diet may significantly improve animal performance (21).…”

Effects of Lysine Cell Mass Supplementation as a Substitute for L-Lysine·HCl on Growth Performance, Diarrhea Incidence, and Blood Profiles in Weaning Pigs

“…Since highly digestible ingredients are used in feed as protein sources for weaning pigs, the feed cost in the weaning diet is more expensive than growing-finishing diets [3,4]. Moreover, a low-protein diet supplemented with synthetic amino acids has been applied to the diet for weaning pigs to reduce the feed cost, diarrhea, and total nitrogen content of pig manure, resulting in an increased use of the synthetic amino acids [5][6][7][8]. Severe climate changes, such as drought, flood, and trade issues between countries have influenced the market prices of protein ingredients and synthetic amino acids.…”