Effect of nursery feeding program on serum haptoglobin, growth performance, and carcass characteristics of pigs reared on commercial farms.

A total of 774 pigs were enrolled in 13 cohorts across 7 commercial farms to examine the effect of nursery feeding program on serum haptoglobin, subsequent growth performance, and carcass characteristics of finishing pigs. Pigs were weaned [23.4 ± 0.2 days of age and 5.3 ± 1.5 kg body weight (BW)] and randomly assigned to either a complex (HC: highly digestible sources of proteins, including animal proteins; N = 346) or simple (LC: corn- and soybean meal-based; N = 340) diet for 37.7 ± 1.7 days over 3 phases (1 pen per diet per cohort; pen was the experimental unit; n = 13); sex was balanced between treatments. Thereafter, pigs received common grower-finisher diets. At a targeted BW of 118 kg, pigs (subset: n = 275 and 258 for HC and LC, respectively) were processed to evaluate carcass characteristics. Nursery feeding program did not influence BW, BW gain, or serum haptoglobin at any stage of production. Feed cost was reduced by $2.82 per pig during the nursery period for the LC-fed pigs (P < 0.001). Loin eye depth, back fat depth, carcass weight, percent lean yield, and carcass gross revenue at slaughter were not influenced by nursery feeding program. Feeding LC nursery diets on commercial farms is a feasible way to reduce feed cost without negatively impacting serum haptoglobin, growth performance during or after the nursery period, or carcass value.

Un total de 774 porcs fut inclus dans 13 cohortes sur sept fermes commerciales afin d'examiner l'effet d'un programme d'alimentation en pouponnière sur l'haptoglobine sérique, les performances de croissance subséquentes, et les caractéristiques des carcasses des porcs en finition. Les porcs furent sevrés [23,4 ± 0,2 jours d'âge et 5,3 ± 1,5 kg de poids corporel (BW)] et assignés au hasard à une diète complexe (HC : source de protéines hautement digestibles, incluant des protéines animales; N = 346) ou une diète simple (LC : moulée à base de maïs et de soya; N = 340) pendant 37,7 ± 1,7 jours sur trois phases (1 parc par diète par cohorte; le parc était l'unité expérimentale; n = 13); les sexes étaient équilibrés entre les traitements. Par la suite, les porcs recevaient une diète de croissance-finition commune. Au poids cible de 118 kg, les porcs (sous-groupe : n = 275 et 258 pour HC et LC, respectivement) étaient abattus pour évaluer les caractéristiques des carcasses. Le programme alimentaire en pouponnière n'a pas influencé le BW, le gain de BW, ou l'haptoglobine sérique à aucun stade de production. Le coût en aliment fut réduit de 2,82 $ par porc durant la période en pouponnière pour les porcs LC (P < 0,001). La profondeur de l'oeil de la longe, l'épaisseur du gras dorsal, le poids de la carcasse, le pourcentage de rendement maigre, et le revenu brut par carcasse à l'abattage n'étaient pas influencés par le programme alimentaire en pouponnière. Nourrir avec une diète LC en pouponnière sur des fermes commerciales est un moyen réaliste de réduire les coûts en aliment sans affecter négativement l'haptoglobine sérique, les performances de croissance durant et après la période en pouponnière, ou la valeur des carcasses.(Traduit par Docteur Serge Messier).

Sexual dimorphism in cardiac triacylglyceride dynamics in mice on long term caloric restriction.

Human studies indicate augmented myocardial lipid metabolism in females, and that sex and obesity interact to predict myocardial fatty acid oxidation and storage. Altered lipid dynamics precede cardiomyopathies, and many studies now address high fat diets. Conversely, caloric restriction (CR), is the most studied model for longevity and stress resistance, including protection against myocardial ischemia. However, no information exists on the effects of long-term caloric restriction (CR) on triacylglyceride (TAG) content and dynamics in the heart. This study explored the effects of CR, sex and age on TAG dynamics in mouse hearts. Male and female SVJ129 mice were fed either normal (ND) or CR diet for 3 or 10 months. In 5-month-old mice, CR similarly decreased cardiac TAG in males (ND: 25.5±4.5 nmol/mg protein; CR: 12.6±2.7, P<0.05) and females (ND: 30.1±4.4; CR: 13.7±1.2) (no significant differences in TAG content were seen between sexes). CR reduced the contribution of exogenous palmitate to oxidative metabolism in males and females, by 15% and 11% respectively, versus ND, without affecting cardiac workload. CR also induced a larger reduction in TAG turnover in male (68%) than female hearts (38%). Interestingly, in 5 month old male mice, CR reproduced the lower TAG turnover rates of middle-aged males (ND 13-month-old male=423±76 nmol/mg protein/min). Thus, long term CR reduces TAG pool dynamics. Despite reduced content, hearts of female mice subjected to CR retained a more dynamic TAG pool than males, while males respond with greater metabolic remodeling of cardiac lipid dynamics.