Roles of the STAT5 transcription factor in neutrophil homeostasy and inflammation

Peer reviewe

Dose and time response of ruminally infused algae on rumen fermentation characteristics, biohydrogenation and Butyrivibrio group bacteria in goats

Background: Micro-algae could inhibit the complete rumen BH of dietary 18-carbon unsaturated fatty acid (UFAs). This study aimed to examine dose and time responses of algae supplementation on rumen fermentation, biohydrogenation and Butyrivibrio group bacteria in goats. Methods: Six goats were used in a repeated 3 x 3 Latin square design, and offered a fixed diet. Algae were infused through rumen cannule with 0 (Control), 6.1 (L-Alg), or 18.3 g (H-Alg) per day. Rumen contents were sampled on d 0, 3, 7, 14 and 20. Results: H-Alg reduced total volatile fatty acid concentration and acetate molar proportion (P 0.10), while H-Alg reduced the total bacteria abundance (P < 0.05). However, this was induced by a significant difference between control and H-Alg on d 14 (-4.43 %). Afterwards, both treatments did not differ as increased variation in the H-Alg repetitions, with in some cases a return of the bacterial abundance to the basal level (d 0). Conclusions: Changes in rumen fermentation and 18-carbon UFAs metabolism in response to algae were related to the supplementation level, but there was no evidence of shift in ruminal biohydrogenation pathways towards t10-18:1. L-Alg mainly induced a transient effect on rumen biohydrogenation of 18-carbon UFAs, while H-Alg showed an acute inhibition and these effects were not associated with the known hydrogenating bacteria

Milk fatty acid composition and associated rumen lipolysis and fatty acid hydrogenation when feeding forages from intensively managed or semi-natural grasslands

In order to evaluate the effect of replacing intensive forage by semi-natural grassland products on rumen lipid metabolism and milk fatty acid composition, four lactating and rumen canulated Holstein cows were used in a 4×4 Latin square design. Four different diets were fed: diet 100 IM - 100% intensively managed silage (IM), diet 20 SPP - 80% IM plus 20% semi-natural but species poor silage (SPP), diet 60 SPP - 40% IM plus 60% SPP and diet 60 SPR - 40% IM plus 60% semi-natural species rich silage (SPR). The silages showed significant differences in total fat content and in proportions of C18:2 n-6 and C18:3 n-3. Despite the reduced dietary supply of C18:3 n-3 with diets 60 SPP and 60 SPR, differences in milk C18:3 n-3 were small, suggesting higher recoveries of C18:3 n-3. Presumably, the latter are related to a higher transfer efficiency of C18:3 n-3 from the duodenum to the mammary gland, since rumen biohydrogenation, estimated from rumen pool size and first order rumen clearance kinetics, were similar among diets. CLA c9t11 in milk from cows fed diet 60 SPR were almost doubled compared to feeding one of the other diets. This has been related to the partial inhibition of rumen biohydrogenation of C18:3 n-3 and/or C18:2 n-6, as suggested by the increased proportions of hydrogenation isomers and reduced stearic acid proportions in rumen pool samples. In conclusion, the results suggest that the use of semi-natural grasslands in the diet of the animals reduce to some extent complete rumen biohydrogenation, which leads to an increase in milk CLA

Content, Pattern and Esterification of Fatty Acids in Fresh Grass in Relation to Extraction Solvents and Sample Storage Conditions

The relatively high content of linolenic acid (C18:3 n-3) in forages has lead to research on the role of forage based feeding strategies in the production of healthier milk. In these studies, forage samples are often stored, although analysis immediately after harvest has been considered to avoid oxidative deterioration and transformation of unsaturated fatty acids (FA) (Christie, 1993; Frankel, 1998). In the current study, we evaluated the effect of different storage conditions (fresh grass samples under liquid nitrogen (liq.N2) or in a cool box during 3h or at -20ºC, -80ºC or in the extraction solvent at -20°C, during 24h) on the total amount of FA extracted, the FA pattern and the extent of FA esterification. The effectiveness of isopropanol to inhibit plant enzyme activity (Hawke, 1973), which has been reported to be particularly high in plant tissues (Christie, 1993), was considered. Measures to avoid thawing losses during sample handling were also compared

Effect of induction of subacute ruminal acidosis on milk fat profile and rumen parameters

High-concentrate diets can lead to subacute ruminal acidosis and are known to result in changes of the ruminal fermentation pattern and mammary secretion of fatty acids. The objective of this paper is to describe modifications in milk fatty acid proportions, particularly odd- and branched-chain fatty acids and rumen biohydrogenation intermediates, associated with rumen parameters during a 6-wk subacute ruminal acidosis induction protocol with 12 ruminally fistulated multiparous cows. The protocol involved a weekly gradual replacement of a standard dairy concentrate with a wheat-based concentrate (610 g of wheat/kg of concentrate) during the first 5 wk and an increase in the total amount of concentrate in wk 6. Before the end of induction wk 6, cows were switched to a control diet because 7 cows showed signs of sickness. The pH was measured continuously by an indwelling pH probe. Milk and rumen samples were taken on d 2 and 7 of each week. Data were analyzed using a linear mixed model and by principal component analysis. A pH decrease occurred after the first concentrate switch but rumen parameters returned to the original values and remained stable until wk 5. In wk 5 and 6, rumen pH values were indicative of increasing acidotic conditions. After switching to the control diet in wk 6; rumen pH values rapidly achieved normal values. Odd- and branched-chain fatty acids and C18:1 trans-10 increased with increasing amount of concentrate in the diet, whereas C18:1 trans-11 decreased. Four fatty acids [C18:1 trans-10, C15:0 and C17:0+C17:1 cis-9 (negative loadings), and iso C14:0 (positive loading)] largely correlated with the first principal component (PC1); with cows spread along the PC1 axis. The first 4 wk of the induction experiment showed variation across the second principal component (PC2) only, with high loadings of anteiso C13:0 (negative loading) and C18:2 cis-9,trans-11 and C18:1 trans-11 (positive loadings). Weeks 5 and 6 deviated from PC2 and tended toward the negative PC1 axis. A discriminant analysis using a stepwise approach indicated the main fatty acids discriminating between the control and acidotic samples as iso C13:0, iso C16:0, and C18:2 cis-9. trans-11 rather than milk fat content. or C18:1 trans-10; which have been used before as indicators of acidosis. This shows that specific milk fatty acids have potential in discriminating acidotic cases

Comparison of methods for determining the fatty acid composition of photosynthetic tissues

The fatty acid (FA) composition of photosynthetic tissue differs from that in other plant or animal tissues. In leaves, the lipid fraction constitutes less than 10% of the dry weight and is mostly located in the chloroplasts. An extraction solvent should dissolve polar lipids readily, but should also overcome interactions between the lipids and the tissue matrix. A mixture of chloroform/methanol (C/M) is commonly used. However, less toxic alternative methods such as hexane/isopropanol (H/I) and ethanol (E) have been suggested. In this preliminary study we compared the effectiveness of these three methods which are used as standard extraction protocols for FA analysis of plant material at three different European Universities. C/M extraction gave the highest total FA content and H/I the lowest, suggesting that C/M is indeed the best general-purpose lipid extraction solvent. Significant differences were also observed for FA composition including the ratio of saturated to unsaturated FA indicating selectivity of the various solvents in extracting different individual FA. Further and more detailed investigations are required to confirm this hypothesi