The influence of sex and gonadectomy on hepatic and brain fatty acid composition, lipogenesis and ß-oxidation.

The aim of this study was to investigate the influence of sex and castration of rats on liver and brain fatty acid profile and liver mRNA expression of genes involved in lipogenesis and ß-oxidation. Castration significantly increased body weight and liver index and decreased serum triglyceride content in the female rats. The fatty acid composition of the liver tissue was influenced by sex and castration. Male rats had higher content of C16:0, C18:1n7, C18:2n6 and C22:5n3, while female rats had higher content of C18:0, C20:4n6 and C22:6n3. Castration of male rats decreased differences caused by sex for C18:2n6, C20:4n6 and C22:6n3. Values for C16:1n7 were higher in the castrated male rats in comparison with all other groups. Liver phospholipids showed a distribution of fatty acids similar to the total lipids. Brain total lipids and phospholipids were not influenced by sex or castration. Castration increased ∆6D gene expression in both the sexes, while ∆5D and ∆9D increased in females and males respectively. Gonadectomy increased expression of the FASN gene in the females and decreased CPT1 and ACOX1 gene expression in the liver tissue of male rats. The observed results of lipid peroxidation, measured by TBARS, were the lowest in the intact females in comparison with all other groups. In conclusion, sex strongly influences both SFA and PUFA in liver tissue, and castration decreases these differences only for PUFA. Castration also influences the expression of the genes involved in lipid metabolism differently in male and female rats, with an increase in lipogenic genes in female rats and a decrease in key genes for mitochondrial and peroxisomal ß-oxidation in male rats.

Effect of dietary hempseed cake on milk performance and haemato-chemicals in lactating Alpine dairy goats.

Owing to the high concentrations of crude protein and beneficial fatty acids, hempseed cake could be a high-quality feedstuff for ruminants. The aim of the present study was to evaluate the effects of hempseed cake on milk production and quality, as well as haemato-chemical parameters in Alpine goats. In total, 28 French Alpine dairy goats were evaluated over 45 days. All goats were fed meadow hay supplemented with 1.2 kg/day feed mixture. The feed mixture in control group contained soybean meal and extruded soybean. In the first experimental group, soybean meal and extruded soybean were partially replaced with 60 g/kg of hempseed cake (HC6). In the second experimental group, soybean meal and extruded soybean were partially replaced with 120 g/kg of hempseed cake (HC12). Feeding goats with HC6 and HC12 did not influence milk yield, although the concentration of milk urea was higher in the HC12 compared to control group. The HC12 decreased the linoleic acid (LA)/linolenic acid (ALA) ratio and glutathione peroxidase activity in the serum. Under the conditions evaluated in this study, the inclusion of HC6 in the diet was optimal with respect to chemical composition of milk and haemato-chemical parameters. Even though HC12 resulted in lowered LA/ALA ratio, which confers functional properties to goat milk, HC12 increased milk urea concentrations, and worsened serum antioxidant status.

Immune and oxidative response to linseed in the diet of periparturient Holstein cows.

The aim of this research was to determine the influence of dietary replacement of n-6 with n-3 polyunsaturated fatty acids on cellular immunity and oxidative stress in the transition period dairy cows. The experiment was conducted on 20 dairy Holstein cows from 3 ± 1 weeks before parturition until the 6th week of lactation. Both groups were fed an iso-energetic and iso-nitrogenous diet. Soybean meal from control (C) group was replaced with linseed in the experimental (LS) group. Cellular immunity and oxidative stress were measured on days -10, 1, 21 and 42 relative to parturition. During the entire experimental period, the proportion of CD45+ cells was lower (P<0.05) in LS group compared with the C group. The phagocytosis ability and phagocytosis index of cows fed with n-3 fatty acids were significantly reduced (P<0.05) compared with the group of cows fed with n-6 fatty acids. The most severe decrease in phagocytosis ability was on day -10 and 1 relative to parturition. The activity of superoxide dismutase (P<0.05) and plasma glutathione peroxidase (P<0.05) increased around calving, although activities were not influenced by dietary treatment. Increased malondialdehyde concentration (P<0.05) was influenced by dietary n-3 fatty acids and the time relative to parturition. The immune suppression was most pronounced during periparturient period. In that matter we can conclude that not only dietary n-3 fatty acids but also oxidative stress, which reached peak at time of parturition, contributed to the reduced cellular immunity during the periparturient period.