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.

Silymarin, a standardized extract from Silybum marianum seed, is a natural hepatoprotector used for the treatment of liver diseases in man. The aim of this study was to investigate its safety and efficacy in periparturient dairy cows. Ten treated and 10 control pregnant dairy cows were paired by parity, body condition score (BCS), health condition and previous milk production. Treatment consisted of daily 10 g per animal of silymarin extract administered as oral drenches, from 10 days prior to the calving date to 15 days after calving. Blood samples and liver biopsies were taken from each animal at 7 and 30 days after calving. Hepatic functions were evaluated by assay of plasma beta-hydroxybutyrate (BHBA), total cholesterol, high-density lipoproteins, low-density lipoproteins, triglyceride and total bilirubin. The histological aspect of the liver was assessed in biopsies. Clinical chemistry values were similar for both groups and effects at different times (day 7 versus day 30; P < 0.05) were attributed to physiological variations in periparturient cows. Histology showed fat accumulation in the liver of both groups, as it is expected in periparturient dairy cows. In treated cows, fat-rich hepatocytes were observed near the central vein. These observations suggest that, at the used dosage, S. marianum extract has no adverse effect on the liver of lactating cows, and presents no objective evidence for a hepatoprotective effect in this species.

Corino, C., Bontempo V. and Sciannimanico D. 2002. Effects of dietary conjugated linoleic acid on some aspecific immune parameters, and acute phase protein in weaned piglets. Can. J. Anim. Sci. 82: 115-117. The aim of this study was to determine the influence of dietary supplementation of conjugated linoleic acid (CLA) on some immune system parameters in piglets. Forty-two weaned piglets, 12.44 ± 1.96 kg liveweight, were fed diets containing 1% sunflower oil (control, C), 0.5% CLA plus 0.5% sunflower oil (T1), and 1% CLA (T2). After 28, d serum lysozyme (1.39, 1.77 and 1.86 µg mL -1 , respectively, for C, T1 and T2 groups; P < 0.01) and total serum immunoglobulin G (IgG) (1548, 1930, 2075 mg dL -1 , respectively, for C, T1 and T2 groups; P< 0.05) were higher in piglets fed dietary CLA. No significant effect on serum α-1-acyl glycoprotein (AGP) was observed. These results support the view that CLA favorably influences immune response.