Effects of diet and storage on fatty acid profile, micronutrients and quality of muscle from German Simmental bulls.

This study evaluated the effect of diet on fatty acid profile, vitamins, trace elements, lipid peroxidation, and quality of longissimus muscle of German Simmental bulls. The effect of storage on fatty acid profile and vitamins was also included. A control group was fed concentrate including soybean, and maize silage/grass silage. Treatment group I (unrestricted) was fed concentrate including rapeseed, and grass silage. Treatment group II (restricted) was fed like treatment group I with a feed restriction period. The treatment diet was not effective to give similar daily live weight gain to the control diet, but it was successful in improving beef fatty acid composition without affecting tenderness and colour (under unrestricted conditions). There were no differences in vitamins and cooking loss, but selenium decreased in treatment groups. Stimulated lipid peroxidation, in samples taken immediately post-mortem, was higher in treatment groups. Polyunsaturated fatty acids decreased, saturated fatty acids and intramuscular fat increased after 14days of storage while vitamins had no significant reduction.

The effects of gender, age and region on macro- and micronutrient contents and fatty acid profiles in the muscles of roe deer and wild boar in Mecklenburg-Western Pomerania (Germany).

Samples of M. longissimus were collected from a total of 203 feral roe deer (n=118) and wild boar (n=85) in two regions of Mecklenburg-Western Pomerania (Germany). The muscle lipid saturated fatty acid proportions of roe deer and wild boar ranged between 33 and 49g/100g total fatty acids and 31 and 35g/100g total fatty acids, respectively. The total n-3 PUFA proportions in roe deer muscle varied between 8.0 and 14g/100g fatty acids, and in wild boar muscle between 2.6 and 6.0g/100g fatty acids. The major vitamin E homologue, α-tocopherol, was determined to be between 5.8 and 13.1mg/kg in roe deer muscles. Lower levels between 1.2 and 4.7mg/kg were measured in wild boar muscles. The iron and zinc concentrations in roe deer and wild boar muscle ranged from 26.3 to 33.9mg/kg and from 17.0 to 21.7mg/kg, and from 13.6 to 39.3mg/kg and 18.1 to 31.9mg/kg, respectively.

Relationship between hair fatty acid profile, reproduction, and milk performance in Holstein Friesian cows.

The aim of this study was to analyze the relationship between the fatty acid profiles of hair of first parity cows and their reproduction and milk performance. Hair samples from 46 German Holstein cows, 50 to 62 d postpartum, were analyzed to assess the relationship. All cows were fed the same diet. The lipid composition of hair was determined by gas chromatography. The fat content in the hair was 0.86%. Hair lipids contributed 75.14% SFA, 15.81% MUFA, and 9.92% PUFA. Cows were classified into a high and a low performance group according to their a) length of the interval from calving to first insemination (CFI), b) 100-d protein yield (100-d PY), and c) length of the interval from calving to conception (CC) and 100-d PY. Cows with short CFI or high 100-d PY or short CC and high 100-d PY had significantly greater proportions of de novo synthesized C12:0 (P < 0.05) compared with the corresponding low performing groups. Increased proportions of C12:0 in the hair were associated with shorter CFI (r = -0.32, P = 0.033) and greater 100-d PY (r = 0.34, P = 0.021). Furthermore, a discriminant analysis with C12:0 as a variable best predicted short CC and high 100-d PY (error rate 33.5%). Greater proportions of de novo synthesized fatty acids in the hair, in particular C12:0, are likely to reflect a sufficient energy availability that is required for fatty acid synthesis in ruminants.

Relationships between intramuscular fat content, selected carcass traits, and fatty acid profile in bulls using a F2-population.

The quality and nutritional value of beef is related to the amount of intramuscular fat (IMF) as well as to its fatty acid composition. In this study the relations between the IMF content and the total fatty acid composition, the fatty acids (FA) of triacylglycerols (TG) and the FA of phospholipids (PL) in longissimus muscle of F(2) Charolais×German Holstein crossbred bulls have been analysed. Polyunsaturated fatty acids (PUFA, C18:2n-6; C18:3n-3) and stearic acid (C18:0) are strongly positively correlated to IMF in longissimus muscle at the quantitative level (mg/100g fresh tissue), but there are negative correlation coefficients for the relative proportion of these fatty acids to IMF. The relationships between IMF and the fatty acid profile of the subfractions TG and PL are lower compared to total muscle fat. Selected carcass fat traits are positively correlated to most of the fatty acids.

Effects of polyunsaturated fatty acids from plant oils and algae on milk fat yield and composition are associated with mammary lipogenic and SREBF1 gene expression.

The main aim of the present study was to examine the effects of long-term supplementing diets with saturated or unprotected polyunsaturated fatty acids from two different plant oils rich in either n-3 or n-6 fatty acids (FAs) plus docosahexaenoic acid (DHA)-rich algae on mammary gene expression and milk fat composition in lactating dairy cows. Gene expression was determined from mammary tissue and milk epithelial cells. Eighteen primiparous German Holstein dairy cows in mid-lactation were randomly assigned into three dietary treatments that consist of silage-based diets supplemented with rumen-stable fractionated palm fat (SAT; 3.1% of the basal diet dry matter, DM), or a mixture of linseed oil (2.7% of the basal diet DM) plus DHA-rich algae (LINA; 0.4% of the basal diet DM) or a mixture of sunflower oil (2.7% of the basal diet DM) plus DHA-rich algae (SUNA; 0.4% of the basal diet DM), for a period of 10 weeks. At the end of the experimental period, the cows were slaughtered and mammary tissues were collected to study the gene expression of lipogenic enzymes. During the last week, the milk yield and composition were determined, and milk was collected for FA measurements and the isolation of milk purified mammary epithelial cells (MECs). Supplementation with plant oils and DHA-rich algae resulted in milk fat depression (MFD; yield and percentage). The secretion of de novo FAs in the milk was reduced, whereas the secretion of trans-10,cis-12-CLA and DHA were increased. These changes in FA secretions were associated in mammary tissue with a joint down-regulation of mammary lipogenic enzyme gene expression (stearoyl-CoA desaturase, SCD1; FA synthase, FASN) and expression of the regulatory element binding transcription factor (SREBF1), whereas no effect was observed on lipoprotein lipase (LPL) and glycerol-3-phosphate acyltransferase 1, mitochondrial (GPAM). A positive relationship between mammary SCD1 and SREBF1 mRNA abundances was observed, suggesting a similar regulation for these genes. Such data on mammary gene expression in lactating cows presenting MFD contribute to strengthen the molecular mechanisms that govern milk fat synthesis in the mammary glands. In purified MEC, the dietary treatments had no effect on gene expressions. Differences between mammary tissue and milk purified MEC gene expression were attributed to the effect of lipid supplements on the number of milk purified MEC and its RNA quality, which are determinant factors for the analysis of gene expression using milk cells.

Effect of dietary fatty acids on expression of lipogenic enzymes and fatty acid profile in tissues of bulls.

This study investigated the effects of dietary linolenic acid (C18:3n-3) v. linoleic acid (C18:2n-6) on fatty acid composition and protein expression of key lipogenic enzymes, acetyl-CoA carboxylase (ACC), stearoyl-CoA desaturase (SCD) and delta 6 desaturase (Δ6d) in longissimus muscle and subcutaneous adipose tissue of bulls. Supplementation of the diet with C18:3n-3 was accompanied by an increased level of n-3 fatty acids in muscle which resulted in decrease of n-6/n-3 ratio. The diet enriched with n-3 polyunsaturated fatty acids (PUFAs) significantly inhibited SCD protein expression in muscle and subcutaneous adipose tissue, and reduced the Δ6d expression in muscle. There was no significant effect of the diet on ACC protein expression. Inhibition of the Δ6d expression was associated with a decrease in n-6 PUFA level in muscles, whereas repression of SCD protein was related to a lower oleic acid (C18:1 cis-9) content in the adipose tissue. Expression of ACC, SCD and Δ6d proteins was found to be relatively higher in subcutaneous adipose tissue when compared with longissimus muscle. It is suggested that dietary manipulation of fatty acid composition in ruminants is mediated, at least partially, through the regulation of lipogenic enzymes expression and that regulation of the bovine lipogenic enzymes expression is tissue specific.

How do n-3 fatty acid (short-time restricted vs unrestricted) and n-6 fatty acid enriched diets affect the fatty acid profile in different tissues of German Simmental bulls?

This study investigated the effect of n-6 (control group) and n-3 polyunsaturated fatty acids (PUFA) supply (treatment group unrestricted) and a short-time feed restriction for n-3 PUFA supply (treatment group restricted) on intramuscular fat content and the total fatty acid composition in different tissues (muscle, subcutaneous fat, liver, serum and erythrocytes) and lipid classes of intramuscular fat of German Simmental bulls (n=25). Exogenous n-3 PUFA caused a higher concentration of the sum of all single n-3 and n-3 long-chain polyunsaturated fatty acids (LC PUFA) in all analysed tissues. Feed restriction compared to control feeding induced a significant decrease of C18:1cis-9 in the phospholipid fraction of longissimus muscle and in subcutaneous fat. The concentration of C18:3n-3 in liver of treatment groups was between 34 and 44% higher compared to control. PUFA in serum and the sum of n-3 PUFA in erythrocytes were significantly higher in both treatment groups compared to control. The synthesis and deposition of n-3 LC PUFA seems to be tissue dependent according to different relative amounts.