Total body amino acid composition of two genetic lines of barrows and gilts from twenty to one hundred twenty-five kilograms of body weight

Abstract Text: A study was conducted to investigate the whole body amino acid (AA) composition profile of barrows and gilts of 2 genetic lines with high and low lean growth rate (high-lean = 375 g of fat-free lean/d; low lean = 280 g of fat-free lean/d) from 20 to 125 kg of BW. A total of 120 growing pigs were slaughtered with a 2 (genetic line) × 2 (sex) × 5 (BW group) factorial arrangement of treatments. At 20 kg of BW and at 25 (or 30) kg BW intervals, six pigs of each genetic line and sex were slaughtered and body components were ground to determine the composition of water, crude protein (CP), fat, ash, and AA. Whole body AA composition was expressed as g/kg BW and g/100g CP. PROC MIXED procedure of SAS (9.4) and contrasts were constructed to analyze the data. Total body AA content for barrows and gilts were 119 vs. 119, 124 vs. 126, 116 vs. 121, 116 vs. 124, and 121 vs. 124 g/kg BW, for BW at 20, 45, 75, 100, and 125 kg, respectively. Total AA content for high- and low-lean genotype were 123 vs. 116, 131 vs. 120, 122 vs. 115, 127 vs. 113, and 129 vs. 115 g/kg BW, for the five BW stages. Between the barrows and gilts, the whole body composition (g/kg BW) of total essential AA and total AA was similar in all BW group except for 100 kg (P < 0.05). From 45 to 125 kg of BW, high-lean genotype showed greater AA content (g/kg BW) of all the essential AA and total AA in all the BW groups. The AA content (g/kg BW) changed in cubic pattern for most AA and total AA along with the increased BW (P < 0.05). The AA profile in whole body CP (g/100g CP) demonstrated a similar AA profile in whole body AA composition between barrows and gilts across BW groups. Genotype affected the AA profile (g/100g CP) for all the essential AA (P < 0.01) except for arginine. Compared with low-lean pigs, high-lean genotype exhibited greater concentrations of isoleucine, lysine, and methionine in CP in all the BW groups greater than 45 kg (P < 0.05). The results indicated that genotype and gender can affect the whole body composition and profile of AA. The genotype of high- and low-lean can impact the AA profile in whole body protein.

Keywords: amino acids, body composition, pig