Raúl Bodas

Animal performance and fatty acid composition of lambs fed with different vegetable oils.

Twenty-seven lambs were used to investigate the effects of the inclusion of 4% hydrogenated palm oil (HPO) or sunflower oil (SFO) in the concentrate on animal performance, carcass and meat quality and fat characteristics and fatty acid composition. Animals (16.2±0.27kg initial weight) were fed concentrate (Control, HPO or SFO) and barley straw ad libitum and slaughtered at 25kg. SFO lambs tended to eat less concentrate than HPO animals (P<0.10). Neither HPO nor SFO affected any of the carcass characteristics studied, meat pH and meat and fat colour (P>0.05). SFO decreased proportions of C16:0, C18:1 cis-11 and C18:3 (P<0.05) and increased C18:1 trans (P<0.001) and C18:2/C18:3 ratio (P<0.05). Atherogenicity index was lower (P<0.05) when SFO was included in the concentrate. HPO did not affected and SFO improved fatty acid composition of fattening lambs without affecting animal performance.

Comparison of the fatty acid profiles in cheeses from ewes fed diets supplemented with different plant oils.

The purpose of this work was to obtain a cheese from ewes milk with a healthier fatty acid (FA) profile. To achieve our aim, 48 ewes (12 per treatment) were fed diets supplemented with 3% of plant oils: palm (used as control), olive (OO), soybean (SO), and linseed (LO). Milk samples from each treatment were collected to manufacture cheeses. The cheesemaking process did not modify the dairy fat FA profile, but OO, SO, and LO did reduce the C12:0 + C14:0 + C16:0 content in dairy fat, thus decreasing the atherogenic index value in the cheeses. Percentages of cis-9 trans-11 C18:2 in cheeses ranged from the 0.43 control value to 0.92, 1.64, and 2.71 with OO, LO, and SO respectively, following the same pattern as trans-11 C18:1. In contrast, trans-10 C18:1 levels were always below 1%. The lowest n-6/n-3 ratio obtained with LO (1.43) suggests that such lipid supplementation would be the most effective nutritional strategy for improving cheese FA profiles.

Meat texture and antioxidant status are improved when carnosic acid is included in the diet of fattening lambs.

Thirty-two Merino lambs fed barley straw and a concentrate alone (CONTROL group) or enriched with carnosic acid [0.6 g kg(-1) dry matter (DM), CARN006 group; 1.2 g kg(-1) DM, CARN012 group] or vitamin E (0.6 g kg(-1) DM, VITE006 group) were used to assess the effect of these antioxidant compounds on meat quality. After being fed the experimental diets for at least 5 weeks, the animals were slaughtered with the 25 kg intended body weight and the different muscles (longissimus lumborum; LL, gluteus medius; GM) were sliced and kept refrigerated under modified atmosphere packaging during 0, 7 and 14 days. The results indicate that carnosic acid seemed to be useful to delay lipid peroxidation in a medium colour-stable muscle such as GM, but this effect was lower than that observed when vitamin E was supplemented to fattening lambs. On the contrary, meat texture and protection against cholesterol oxidation were equally improved with both compounds.

Carnosic acid dietary supplementation at 0.12% rates slows down meat discoloration in gluteus medius of fattening lambs

Thirty-two Merino lambs fed barley straw and a concentrate alone (CONTROL) or enriched with vitamin E (VITE006) or carnosic acid (CARN006; CARN012) were used to assess the effect of these antioxidant compounds on meat quality attributes. The animals were slaughtered after being fed for at least 5weeks with the experimental diets. The longissimus lumborum samples of VITE006, CARN006 and CARN012 groups showed higher values (P<0.001) of L* (lightness) through the complete storage period under modified atmosphere when compared to the CONTROL group. Moreover, the VITE006 and CARN012 samples revealed lower discoloration when compared to the CONTROL group, these differences being more apparent in a less color stable muscle such as gluteus medius (P<0.05 for hue after 14days of refrigerated storage). Meat sensory traits were not significantly affected by carnosic acid and microbiological analyses were not conclusive at the doses administered.

Feeding vegetable oils to lactating ewes modifies the fatty acid profile of suckling lambs.

The objective of this study was to evaluate the effects of vegetable oil supplementation of ewe diets on the performance and fatty acid (FA) composition of their suckling lambs. Forty-eight pregnant Churra ewes (mean BW 64.3±0.92 kg) with their 72 newborn lambs (prolificacy=1.5) were assigned to one of four experimental diets, supplemented with 3% of hydrogenated palm (PALM), olive (OLI), soya (SOY) or linseed (LIN) oil. Lambs were nourished exclusively by suckling from their respective mothers. Ewes were milked once daily, and milk samples were taken once a week. When lambs reached 11 kg, they were slaughtered and samples were taken from musculus longissimus dorsi (intramuscular fat) and subcutaneous fat tissue. No changes were observed in milk yield, proximal composition or lamb performance (P>0.10). Milk and lamb subcutaneous and intramuscular fat samples from the PALM diet had the highest saturated fatty acid concentration, whereas those of the OLI, SOY and LIN diets had the lowest (P<0.05). The greatest monounsaturated fatty acid concentration was observed in milk from ewes fed OLI, and the least in milk and in lamb subcutaneous and intramuscular fat samples from LIN and PALM diets. Milk and lamb fat from ewes fed PALM displayed the highest 16:0 proportion and the lowest 18:0 (P<0.05). There were higher concentrations of cis-9 18:1 in OLI samples (P<0.05), more 18:2n-6 in SOY lambs and milk fat (P<0.001) and the highest levels of 18:3n-3 and 20:5n-3 in LIN samples (P<0.01). Milk and lamb subcutaneous and intramuscular samples from SOY and LIN diets contained the most cis-9, trans-11 conjugated linoleic acid, whereas PALM samples had the least (P<0.01). Sheep diet supplementation with different oils, constituting up to 3% of their diets, resulted in changes in the FA composition of milk and the subcutaneous and intramuscular fat of suckling lambs, but did not affect either milk production or lamb performance.

The liver antioxidant status of fattening lambs is improved by naringin dietary supplementation at 0.15% rates but not meat quality

Twenty Assaf lambs fed barley straw plus a concentrate alone (CONTROL group) or enriched with naringin (1.5 g/kg DM, NARINGIN group) were used to assess the effect of this polyphenolic compound on meat quality attributes. Serum samples were collected for 7 weeks, then the animals were slaughtered and the livers and longissimus thoracis et lumborum muscles extracted for analysis. Triacylglycerol levels in the serum samples tended to show (P = 0.087) lower average values for the NARINGIN group when compared with the CONTROL, but no differences were observed when the meat was analysed for the intramuscular fat content. Lower thiobarbituric acid-reactive substances procedure (TBARS) values (P < 0.001) in the liver of the NARINGIN group were detected, probably as a consequence of naringenin accumulation in this organ. No significant differences were observed in the meat samples concerning TBARS or colour evolution during refrigerated storage, as not enough naringenin would have reached the muscle. Independent of naringin administration, the low levels of the most atherogenic oxysterols must be highlighted as the most important quality score in the lamb meat samples studied.

Carcass and meat quality of Assaf milk fed lambs: Effect of rearing system and sex.

The effect of sex and rearing system on growth and carcass and meat characteristics of milk fed Assaf lambs was studied. Thirty-six lambs, 18 males and 18 females were used. Twelve lambs remained with their mothers throughout the experiment (NR). Within 24-36h of birth, the rest were housed individually and fed twice a day ad libitum (AAR) or at 70% of ad libitum consumption (RAR) with reconstituted cows milk. Sex did not affect animal performance, yet females showed higher carcass and non-carcass fat deposits. NR lambs showed greater BWG than AAR fed lambs, and AAR, higher than the RAR. Differences between naturally and artificially reared lambs in CCW and killing out percentage were not significant. Empty digestive tract and mesenteric fat weights were greater for RAR than NR lambs, with the AAR lambs demonstrating intermediate values; conversely, omental fat was greater in NR lambs. Carcass ether extract content was greater for NR lambs, possibly due to the greater growth. Use of ad libitum cows milk substitute in suckling lambs twice a day resulted in less body weight gain but similar killing out percentages compared to naturally raised lambs. A 70% restricted supply increased the days in suckling and reduced carcass fatness and compactness. Except for water loss, which was less in NR than artificially fed lambs, no differences were found in meat characteristics.

Effects of linseed and quercetin added to the diet of fattening lambs on the fatty acid profile and lipid antioxidant status of meat samples.

Thirty-two Merino lambs fed barley straw and a concentrate formulated either with palm oil (CTRL group) or with linseed (+LS group), both alone or supplemented with quercetin (+QCT group or +LS+QCT group) were used to assess the effects of these dietary supplements on meat quality attributes. After being slaughtered, the longissimus thoracis muscles were used to study the fatty acid (FA) profile in detail, whilst longissimus lumborum slices were stored under refrigerated conditions to determine the lipid stability. Linseed increased the content of highly unsaturated n-3 long-chain fatty acid (20:5n-3; 22:5n-3; 22:6n-3). Interestingly, a significant increment of rumenic acid content (9c,11t-18:2) was observed when this seed was administered together with dietary quercetin. Moreover, the feeding of quercetin resulted in a reduction in the proportion of saturated FA and a decrease in lipid peroxidation of meat when the lambs were fed linseed. In conclusion, from both a nutritional and a commercial (shelf-life) point of view, it may be useful to include a source of quercetin when lambs are fed linseed diets.

Quercetin dietary supplementation of fattening lambs at 0.2% rate reduces discolouration and microbial growth in meat during refrigerated storage

Thirty-two Merino lambs fed barley straw and a concentrate formulated either with palm oil (CTRL group) plus quercetin (QCT group) or flaxseed (FS group) plus quercetin (FS-QCT group) were used to assess the effects of this flavonoid on meat quality attributes. The animals were slaughtered after being fed for at least 5 weeks with the experimental diets. Chemical composition of longissimus thoracis (LT) muscle was not different among treatments. The longissimus lumborum (LL) samples of QCT and FS-QCT groups revealed lower discolouration (hue angle) when compared to the CTRL and FS lambs (P<0.05), whereas extract release volume (ERV) and microbiological data jointly suggest that flaxseed and quercetin may reduce the growth of microbial populations responsible for meat spoilage in quadriceps femoris (QF).

Effects of inactivated and live cells of Saccharomyces cerevisiae on in vitro ruminal fermentation of diets with different forage: concentrate ratio

SUMMARY The effects of yeast Saccharomyces cerevisiae, either inactivated (by osmotic pressure, designated IY) or provided as a culture containing live yeast cells (YC), on ruminal fermentation of two different diets were investigated in vitro. Total mixed rations (TMR) having forage:concentrate ratios of 0·6:0·4 (medium–high forage diet) and 0·2:0·8 (low-forage diet) were incubated in batch cultures of mixed ruminal micro-organisms to which either IY (to reach concentrations of 500 and 250 mg product/l incubation medium) or YC (at a concentration of 150 mg product/l) were added directly as powder. To evaluate the effects of the additive on ruminal microbial population, sheep used as donors of rumen fluid wereallocatedto three experimental groups: Control(no additive), IYand YC, that received a diet with the corresponding additive for 10 days. With both diets, YC decreased ruminal pH compared to control, whereas IY had no effect. Adding yeast products to the high-fibre diet affected total volatile fatty acid (VFA) production and VFA composition, in general with a slight increase in IY and a significantly greater increase in response to the addition of YC. Ammonia nitrogen (P=0·006), total gas production (P<0·001) and in vitro dry matter disappearance (IVD) (P<0·001) showed the highest values with YC. Methane production was higher than the control when the IY inoculum was used, and increased even more with the YC inoculum (P<0·001). With the high-concentrate TMR, no effects on total VFA concentration were observed when yeast additives were used. Similar trends were shown for lactate and methane production and total gas production, where values tended to be higher when using the YC inoculum (P values of 0·055, <0·001, 0·006 and <0·001, respectively). After 144 h of incubation, differences were observed only with the high-fibre diet in the cumulative gas productionat24 h ofincubationandinthe averagefermentation rate, which wasgreater with YC,although the asymptotic gas production was not affected. These results indicate that live yeasts affect ruminal fermentation slightly morethaninactivatedyeasts,althoughbothproductsrequirearegularadministrationandsome adaptation oftheruminalmicrobialpopulationforthestimulatoryeffectstobecomeapparent.Theeffects ofyeastsonruminal fermentation are diet-dependent, being more noticeable with a high-fibre substrate, and subtle with a highconcentrate diet.