Location: Reproduction ResearchTitle: Growth and body composition, feed intake, and carcass composition traits of developing gilts fed different dietary lysine and metabolizable energy levels Author
|Calderon Diaz, Julia - Iowa State University|
|Vallet, Jeffrey - Jeff|
|Prince, Terry - Prince Nutrition Service Llc|
|Phillips, C - Murphy Brown Llc|
|Dedecker, A - Murphy Brown Llc|
|Stalder, Kenneth - Iowa State University|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2015
Publication Date: 3/1/2015
Citation: Calderon Diaz, J.A., Vallet, J.L., Prince, T.J., Phillips, C.E., DeDecker, A.E., Stalder, K. 2015. Growth and body composition, feed intake, and carcass composition traits of developing gilts fed different dietary lysine and metabolizable energy levels [abstract]. Journal of Animal Science. 93(Supplement 2):68 (Abstract #152).
Technical Abstract: The objectives of this study were to manipulate the lean:fat ratio by feeding diets differing in lysine and ME content to replacement gilts housed in groups from 100 d of age until slaughter (approximately 260 d of age) to evaluate lysine and caloric efficiency between dietary treatments. Crossbred Large White × Landrace gilts (n = 1221) housed in groups were randomly allotted to 6 corn-soybean diets formulated to provided 2 standardized ileal digestible lysine levels [100% (HL), 85% (LL)] and 3 ME levels [90% (LME), 100% (MME), 110% (HME)] at 100 d of age. The 100% lysine and 100% ME were based on an informal survey from the U.S. commercial swine industry to obtain average levels that are currently fed to developing gilts. Gilts were weighed and backfat thickness and loin area were recorded at the beginning of the trial and then every 28 days. Feed intake (FI) was recorded as feed disappearance within the pen at 2-wk intervals. Biweekly and daily lysine (g) and ME (Mcal) consumed were calculated based on diet formulations. At slaughter, hot carcass weight was recorded. Data were evaluated for normality and analyzed using mixed model methods. There were no differences between lysine or ME levels for growth and body composition except for backfat, which was slightly greater for gilts fed a HME (~2 mm). Gilts fed HME diets had a lower FI but a greater ME intake compared with gilts fed LME (P < 0.05). Additionally, gilts fed the HME diet had lower FI and lysine intake per kg of BW gain when compared to gilts fed LME or MME diets (P < 0.05). However, there was no difference in the Mcal consumed per kg of BW gain among treatments (P > 0.05). Carcasses from gilts fed the HME diet were 3.3 kg and 2.5 kg heavier than those from gilts fed the LME or MME diets (P < 0.05). Despite significant differences in the lysine:ME ratio in the diets, no changes in growth or body composition traits occurred, likely due to compensatory changes in FI in response to dietary ME content. Caloric efficiency was similar among treatments. Carcass weight differences at slaughter were likely related to organ size and organ weight, which could have been affected by FI. Further research is necessary to identify the optimal lysine-to-energy ratio to manipulate growth and body composition in replacement gilts fed ad libitum.