Reduction of the crude protein content of diets supplemented with essential amino acids for piglets weighing 15 to 30 kilograms

Abstract

-Two experiments were carried out to evaluate the reduction of crude protein (CP) in diets supplemented with synthetic amino acids for piglets of 15 to 30 kg. In the performance assay (Exp I), 60 piglets with initial weight of 15.34±0.87 kg and final weight of 30.08±1.59 kg were distributed in a randomized block design with six replicates, five treatments and two animals per experimental unit. The treatments consisted of five diets in which the CP was reduced by 1.5 percentage points, resulting in low-protein diets (19.24, 17.74, 16.24, 14.74 and 13.24%), meeting the requirements of amino acids with inclusion of L-lysine, DL-methionine, L-threonine, L-tryptophan, L-valine and L-isoleucine. The average daily gain and feed conversion according to the Linear Response Plateau model (LRP) were estimated at 14.23 and 14.79% of CP, respectively. As the CP levels were reduced, there was an increase in the essential:non-essential amino acids ratio. The plasma urea concentration decreased linearly, indicating that there was a better use for amino acids with the CP reduction. In the nitrogen balance (Exp II), 30 crossbred barrow piglets with average weight of 21.69±4.46 kg were housed in metabolic cages, distributed in a completely randomized design with five treatments and six replicates, and the experimental unit consisted of a piglet. The biological protein value in the diets remained above the ideal (70%), in which the level of 13.24% CP corresponded to the highest value. There was no difference in levels of urea in blood and urine. Reduction of protein levels is efficient in decreasing the pollution effect in the excreta, with lower nitrogen excretion in feces and urine.

Crude protein reduction with amino acid supplementation in tambaqui fingerling diets

“…This is probably due to the better amino acid balance in the diets with reduced CP content and limited amino acid supplementation (BOMFIM et al, 2008;TOLEDO et al, 2014). This response pattern is similar to that observed in grass carp (Ctenopharyngodon idella) by Gan et al (2012).…”

“…In this concept, the amino acid lysine is used as reference for the essential amino acids, mainly because it is industrially available, there is a significant amount of information regarding its requirements, it is easy to analyze, and a large proportion is used in protein synthesis (NRC, 2011;FRACALOSSI;CYRINO, 2013;TOLEDO et al, 2014).…”

Impacts of Macronutrients on Gene Expression: Recent Evidence to Understand Productive and Reproductive Performance of Livestock

“…Dietary proteins are the primary suppliers of necessary AA for livestock species. Thus, adequate supply of dietary protein is essential in order to provide different AA and small peptides to the animal for their proper growth and development (Toledo et al, 2014). In contrast, inadequate supply of protein may lead to suboptimal growth and reproduction of livestock animals .…”

“…Now, the key factor in formulating new generation diets for livestock requires indepth knowledge of the regulation of protein & AA metabolism and the function of digestive system in association with digestive enzyme related gene expressions. Although, several studies have been conducted highlighting the role of dietary protein and AA on weight gain Kim et al, 2015), productive and reproductive performance (Galassi et al, 2010;Toledo et al, 2014) in pigs, very little is known about the underlying genetic mechanism. In recent years, few studies tried to correlate the dietary supplementation/ manipulation of macronutrients over gene expression.…”

Redução da proteína bruta em rações sobre os balanços metabólicos de suínos mantidos em diferentes condições térmicas

“…Os avanços na determinação das exigências de aminoácidos para suínos, associada a um aumento da disponibilidade de aminoácidos sintéticos, permite a redução dos níveis de proteína bruta da dieta, com o objetivo de fornecer aos suínos uma relação equilibrada de aminoácidos que atendam as suas necessidades, proporcionando maior eficiência de deposição de proteína e menor excreção de nitrogênio (TOLEDO et al, 2014).…”