Starch and oil in the donor cow diet and starch in substrate differently affect the in vitro ruminal biohydrogenation of linoleic and linolenic acids

Trans isomers of fatty acids exhibit different health properties. Among them, trans-10,cis-12 conjugated linoleic acid has negative effects on milk fat production and can affect human health. A shift from the trans-11 to the trans-10 pathway of biohydrogenation (BH) can occur in the rumen of dairy cows receiving high-concentrate diets, especially when the diet is supplemented with highly unsaturated fat sources. The differences of BH patterns between linoleic acid (LeA) and linolenic acid (LnA) in such ruminal conditions remain unknown; thus, the aim of this work was to investigate in vitro the effects of starch and sunflower oil in the diet of the donor cows and starch level in the incubates on the BH patterns and efficiencies of LeA and LnA. The design was a 4 × 4 Latin square design with 4 cows, 4 periods, and 4 diets with combinations of 21 or 34% starch and 0 or 5% sunflower oil. The rumen content of each cow during each period was incubated with 4 substrates, combining 2 starch levels and either LeA or LnA addition. Capillary electrophoresis single-strand conformation polymorphism of incubates showed that dietary starch decreased the diversity of the bacterial community and the high-starch plus oil diet modified its structure. High-starch diets poorly affected isomerization and first reduction of LeA and LnA, but decreased the efficiencies of trans-11,cis-15-C18:2 and trans C18:1 reduction. Dietary sunflower oil increased the efficiency of LeA isomerization but decreased the efficiency of trans C18:1 reduction. An interaction between dietary starch and dietary oil resulted in the highest trans-10 isomers production in incubates when the donor cow received the high-starch plus oil diet. The partition between trans-10 and trans-11 isomers was also affected by an interaction between starch level and the fatty acid added to the incubates, showing that the trans-10 shift only occurred with LeA, whereas LnA was mainly hydrogenated via the more usual trans-11 pathway, whatever the starch level in the substrate, although the bacterial communities were not different between LeA and LnA incubates. In LeA incubates, trans-10 isomer production was significantly related to the structure of the bacterial community

Wool characteristics of Libyan Barbary sheep in north-eastern Libya: I. Fiber diameter and staple length

In this study wool characteristics of Libyan sheep in north-eastern Libya were investigated in a coastal region extended from El-Marj (32 25 N and 20 30 E) to Emsaad at the north-eastern border of the country (31 33N, 25 6 E). Twelve locations, one flock per flock were studied. Three sites have been sampled from each animal (Shoulder, mid-side and breech). Mean staple length and fiber diameter were 12.16cm and 38.43 µm respectively. In this study, staple length and fiber diameter didn’t significantly vary between locations studied. Sample site on the body of the animal significantly affect both staple length and fiber diameter, with breech position samples showed the shortest staple length and the thickest fiber diameter (P< 0.05). There was no difference between samples taken from mid-side or shoulder in all measured traits. Results of this study showed that Barbary sheep raised in the eastern part of the country characterized by a long staple and a large fiber diameter, and then confirmed the previous studies studies stated that this breed could be classed as a long carpet wool breed. Samples taken from mid-side position could be representative of Barbary sheep fleec