Effects of Chain Length and Saturability of Fatty Acids on Phospholipids and Proteins in Plasma Membranes of Bovine Mammary Gland.

Free fatty acids (FFAs) in plasma are essential substrates for de novo synthesis of milk fat, or directly import into mammary cells. The physico-chemical properties of mammary cells membrane composition affected by FFAs with different chain lengths and saturability are unclear yet. Employing GC, FTIR and fluorescence spectroscopy, the adsorption capacity, phospholipids content, membrane proteins conformation, lipid peroxidation product, and free sulfhydryl of plasma membranes (PMs) interacted with different FFAs were determined. The mammary cells PMs at 38 and 39.5 °C showed different adsorption capacities: acetic acid (Ac) > stearic acid (SA) > ß-hydroxybutyric acid (BHBA) > trans10, cis12 CLA. In the FTIR spectrum, the major adsorption peaks appeared at 2920 and 2850 cm-1 for phospholipids, and at 1628 and 1560 cm-1 for membrane proteins. The intensities of PMs-FFAs complexes were varied with the FFAs species and their initial concentrations. The ß-sheet and turn structures of membrane proteins were transferred into random coil and α-helix after BHBA, SA and trans10, cis12 CLA treatments compared with Ac treatment. The quenching effects on the fluorescence of endogenous membrane protein, 1, 8-ANS, NBD-PE, and DHPE entrapped in PMs by LCFA were different from those of short chain FFAs. These results indicate that the adsorption of FFAs could change membrane protein conformation and polarity of head group in phospholipids. This variation of the mammary cells PMs was regulated by carbon chain length and saturability of FFAs.

Effects of Maternal Undernutrition during Mid-Gestation on the Yield, Quality and Composition of Kid Meat Under an Extensive Management System.

Nutritional status during mid-gestation is often ignored under extensive husbandry. This study aimed to examine the effect of maternal undernutrition during mid-gestation on kid meat production under an extensive system. Twenty-seven goats (45 ± 3 d of gestation) were randomly assigned to an unrestricted group (100% of nutrient requirements), or a restricted group (60% of nutrient requirements from 45 to 100 d of gestation, and then re-alimented to 100%). Among the offspring, 16 eligible kids (eight per treatment) were selected, based on birth type and survival, and were harvested to evaluate the meat yield, quality, and composition at 90 d after birth. Maternal undernutrition reduced the body weight and size, average daily gain and hot carcass weight of the kids (p < 0.05). The lightness of the meat at 45 min postmortem was increased (p = 0.029) in the restricted kids. Apart from an increase in tyrosine concentration (p = 0.046), the proximate composition and the amino acid and fatty acid profiles were unaffected in the restricted kids (p > 0.05). Overall, maternal undernutrition during mid-gestation decreased the yield of kid meat, but did not significantly modify the quality and composition. These results highlight the importance of nutrient status during mid-gestation in the meat production of small ruminants under an extensive regime.

Variety diversity effect on the chemical composition and dry matter degradation characteristics of residue and by-products of oil palm fruits.

The materials palm press fibre (PPF), palm calyx (PCL) and palm oil sludge (POS) obtained from three varieties of oil palm: dura, oleifera and tenera were investigated for the effect of variety on their nutritive value. Analysis of proximate composition, cell wall fractions, some mineral concentration as well as in-situ dry matter degradation in the rumen of steers were carried out. Significant effects of materials (i.e. PPF, PCL and POS) as well as variety (i.e. dura, oleifera and tenera) were noticed in all the parameters studied except sodium (Na) and organic matter (OM) components. Crude protein (CP) values in all the varieties were lowest in PCL (3.15-5.48%) and highest in POS (9.02-10.02%), while crude fibre (CF) values were highest in PCL (33.00-46.19%) and lowest in POS (3.15-5.48%). The upper and lower values respectively for CP and CF in the materials were in most cases for the tenera variety. The cell wall fractions (NDF, ADF, Lignin, cellulose and hemicellulose) were all higher in PCL and lowest in POS. In the three varieties, POS had highest concentration of Mg (0.117-0.231 g/100 g), K (1.21-2.33 g/100 g) and Cu (75.07-87.34 mg/kg) but lowest content of Ca (0.016-0.089 g/100 g) while PPF had lowest concentration of Mg (0.031-0.039 g/100 g) and Cu (20.96-22.28 mg/kg). Iron (Fe, mg/kg) values were generally high, but highest in PCL (2015.41-4042.16). Dry matter degradability and effective degradability values were best in POS irrespective of the variety and least in PCL. Among the three varieties, dry matter degradation characteristics of tenera were the best and oleifera the least. Generally the residue and by-products irrespective of the variety of oil palm they are obtained from can be ranked for their nutritive value as POS > PPF > PCL, while nutritive ranking based on variety is tenera > dura > oleifera. Conclusively, POS and PPF from any variety of oil palm could be adopted directly as feed resources for ruminant livestock, while PCL will require hydrolytic nutritive value enhancement treatment. Ruminant livestock will however be at an advantage if materials from tenera variety are fed.