We studied the effects of conjugated linoleic acid (CLA) on metabolic and immunologic variables in lactating sows and piglets. Gestating sows (n = 16) were assigned to 1 of 2 weight- and parity-matched groups supplemented with 0% (C) or 0.5% (T) of a CLA preparation containing 50% CLA isomers. Supplementation started in late pregnancy and continued throughout lactation. At weaning, 80 piglets, half from each group of sows, were assigned to 0% CLA (C) or 0.5% CLA (T). Thus, there were four groups of 20 piglets: C-C, C-T, T-T, and T-C. Body weight and the number of piglets per litter at birth and weaning, and the chemical composition of colostrum did not differ among the groups. CLA affected the fatty acid composition of colostrum fat; palmitoleic and gamma-linolenic acid were significantly lower compared with controls, whereas eicosenoic and eicosatrienoic acids were significantly higher. Feeding CLA increased (P < 0.05) colostrum IgG in sows. Sows fed CLA had higher (P < 0.05) serum leptin, IgG, and lysozyme. Nursing piglets from CLA-fed sows had significantly higher (P < 0.01) serum lysozyme and IgG. Consumption of CLA did not affect postweaning growth. Postweaning piglets fed CLA (T-T, C-T) had a higher IgG titer at 25 d (P < 0.05) and 35 d (P < 0.01) after weaning. Serum lysozyme was also higher at 25 d (P < 0.05) in CLA-fed piglets (T-T, C-T). At 35 d, serum alpha-1 acylglicoprotein was lower (P < 0.05) in piglets fed CLA. Dietary CLA had a positive effect on immunologic variables in lactating sows and piglets.

ABSTRACT:We investigated the effects of conjugated linoleic acid (CLA) supplementation on growth, feed efficiency, carcass characteristics, meat quality, lipogenesis, and lipid metabolism in rabbits. One hundred forty-four New Zealand White rabbits, half males, half females, age 55 d, mean 1.8 kg BW, were randomly assigned to three weight-and sex-balanced feeding groups in which conventional pelleted diets were supplemented with 0, 0.25, or 0.5% of a CLA preparation. The CLA preparation contained 65% CLA isomers. Twelve rabbits (six males and six females from each group) were slaughtered at each of three slaughtering trials (2.5, 2.8, and 3.1 kg BW, or 76, 90, and 104 d of age). Conjugated linoleic acid supplementation did not influence growth performance (P ≥ 0.05) or carcass characteristics but reduced perirenal fat at heavier slaughtering weights (P = 0.09 at 2.8 kg BW; P < 0.01 at 3.1 kg BW). Conjugated linoleic acid reduced acetyl-CoAcarboxylase (CBX) activity in liver (P < 0.05) and adi-

Conjugated linoleic acid isomers may affect the onset and severity of several diseases, including tumors, atherogenesis, and obesity. They may also modulate the immune response. However, little information regarding the most advantageous duration of CLA supplementation is available. The purpose of this study was to determine whether the length of dietary CLA supplementation of a sow affects growth, immune components, and metabolic and hormonal factors in lactating sows and piglets. Gestating sows were fed a control (0%) and a 0.5% CLA-supplemented diet beginning 7 d before parturition and ending 7 d postpartum (T1), or until weaning (T2; 7 sows per treatment). Colostrum and sow and piglet blood samples were collected for the determination of serum metabolite concentrations and immunoglobulin titer. Piglet BW at weaning were greater (P < 0.05) in the CLA groups compared with the control. Dietary CLA supplementation increased (P < 0.05) serum thyroxine concentration in sows, but serum insulin, glucose, NEFA, IGF-I, and leptin concentrations were not affected by CLA supplementation. Colostral IgG, IgA, and IgM titers were greater in sows fed CLA than in control sows (P < 0.05). At weaning (21 d), serum IgG titer of the piglets was greater (P < 0.05) in the T1 and T2 groups than the control group, but at 13 d postweaning, a difference (P < 0.05) was observed between the control and T2 group. The results from this study indicate potential beneficial effects of 0.5% dietary CLA supplementation from 7 d before parturition until 7 d postpartum in improving BW at weaning and immune components in piglets.

-Five Haflinger mares were hand-milked at 0 h (pre-suckle) and 6 h (postsuckle), 12, 24, 48, 72 and 96 h after parturition. Total solids, protein, fat, lactose, calculated gross energy content, leptin and non-protein nitrogen components (urea, a-amino nitrogen, creatinine and allantoin) were determined. The levels of the major constituents differed significantly in pre-suckle colostrum from subsequent samples. Leptin levels were the highest in whole (9 ng . mL -1 of immunoreactive human equivalent HE ± 0.48 ng . mL -1 , SEM) and skimmed (7.8 ng HE . mL -1 ± 0.52 ng . mL -1 , SEM) pre-suckle colostrum, declined sharply at 6 hours postpartum, and more slowly subsequently. Mean urea concentration was constant at around 5.0 mM, while a-amino N increased over the observation period and creatinine and allantoin decreased. These findings provide a further indication that mares' milk can be regarded as a functional food. mares' milk / colostrum / major constituents / leptin / non-protein nitrogenRésumé -Principaux constituants, leptine et métabolites d'azote non protéique dans le colostrum et le lait de jument. Cinq juments Haflinger ont été traitées à la main aux temps 0 (avant tétée) et 6 (après tétée), 12, 24, 48, 72 et 96 heures après le poulinage. Les paramètres évalués sur ces échantillons ont été les principaux constituants de la sécrétion mammaire (matière sèche, protéines, lipides, lactose), le contenu énergétique brut et la leptine ; en plus, on a considéré les teneurs en urée, a-aminoacides, créatinine et allantoïne. Une différence significative a été observée entre les valeurs enregistrées dans le colostrum prélevé avant la tétée et dans les autres échantillons. De même, des variations dynamiques concernant la leptine immunoréactive ont été relevées au cours de l'essai : les valeurs étaient les plus fortes dans le lait entier (9 ng . mL -1 équivalent de leptine humaine HE ± 0,48 ng . mL -1 , SEM) et dans le colostrum écrémé (7,8 ng HE . mL -1 ± 0,52 ng . mL -1 , SEM) prélevés avant la tétée. La concentration en urée était en moyenne de 5,0 mM et la concentration en azote des a-aminoacides dénote des bilans différents par rapport à celui mis en évidence pour la créatinine et pour l'allantoïne. Ces résultats contribuent à faire considérer le lait de jument comme un aliment fonctionnel.lait de jument / colostrum / constituants du lait / leptine / non-protein nitrogen Reprod. Nutr. Dev. 42 (2002) 65-72 65