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PSV-1 Effects of the protein level on growth performance and carcass grading in fattening pig fed ad libitum. J Anim Sci 2019. [DOI: 10.1093/jas/skz122.392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Reducing dietary crude protein (CP) with synthetic amino acids (AA) supplementation is beneficial for sustainable swine industry. However some discrepancies regarding the consequences on growth performance are observed. Therefore, this trial aimed to assess the effect of dietary CP level on growth performance of pigs from 35 to 113 kg BW. Growth performance of 63 pigs fed ad libitum and allocated to three groups (HH, MM and LL) was compared. Each group received one level of CP (‘H’ for High, ‘M’ for Medium and ‘L’ for Low) during growing (d0–d35) and finishing (d35–slaugther day) periods: 15.1%, 16.2%, 17.2% and 13.0%, 14.0%, 15.1% respectively. Diets were mostly based on wheat, corn and soybean meal. Within each feeding phase, diets were formulated to be similar in apparent total tract digestible phosphorus, net energy and standardized ileal digestible (SID) essential AA, the SID Lys levels being 0.95% and 0.78% during the growing and finishing period respectively. Data were analyzed using a linear model (R, 3.1.2) with individual as the experimental unit as feed intake, body weight and carcass grading were individually recorded. From d0 to d14 and from d35 to d63, average daily gain (ADG) and Growth:Feed ratio (G:F) were significantly reduced as the CP level decreased (P < 0.05) while average daily feed intake (ADFI) remained unaffected by the dietary treatments. From d14 to d35 and in late finishing period (d63-slaugther day), growth performance was not significantly affected by the dietary CP level. Over the 82-d of the experiment, G:F was significantly higher for ‘HH’ pigs (P < 0.01). Overall, ADG tended to be reduced as CP levels decreased (P = 0.10). There was no difference among treatments for parameters concerning carcass grading (lean meat percentage and meat yield). In conclusion, reducing CP levels while maintaining essential AA levels impaired growth performances of pigs.
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