Francisco Javier Giráldez

Ability of near infrared reflectance spectroscopy (NIRS) to estimate physical parameters of adult steers (oxen) and young cattle meat samples

The potential of NIRS-based models to predict several physical parameters of oxen and young cattle beef protected by a quality mark was evaluated. Fifty-three and 67 samples of Longissimus thoracis muscle corresponding to oxen and young cattle reared in extensive conditions were analyzed for pH, colour (L(∗), a(∗), b(∗)), water holding capacity (WHC) and Warner-Braztler shear force (WBSF), according to the conventional methods. Several factors which might have jeopardized the prediction of pH, a(∗), WHC and WBSF by NIRS are considered in the discussion section. However, the best NIR calibrations, tested by full cross-validation, were for L(∗) (R(2)=0.869; SE(CV)=1.56) and b(∗) (R(2)=0.901; SE(CV)=1.08) colour parameters in meat samples from young cattle. It can be concluded that NIRS could be a useful tool for estimating the colour of young cattle meat samples, primary consideration for consumers when making purchasing decisions.

Potential use of near infrared reflectance spectroscopy (NIRS) for the estimation of chemical composition of oxen meat samples

Near infrared reflectance spectroscopy (NIRS) was evaluated as a tool to estimate several chemical parameters of oxen meat protected by a quality mark. Fifty-three samples of longissimus thoracis muscle corresponding to oxen reared in extensive conditions were homogenized and scanned over the NIR spectral range (1100-2500nm). Immediately after scanning, the samples were analyzed for crude protein (CP), myoglobin, collagen, ether extract (EE), gross energy (GE), dry matter (DM) and ash content, according to the official methods. Best NIR calibrations for chemical composition tested by cross-validation showed R(2) and SE(CV) of 0.874 and 20.33gkg(-1) DM (CP), 0.924 and 16.22gkg(-1) DM (EE), 0.941 and 0.293MJkg(-1) DM (GE) and 0.874 and 6.75gkg(-1) FM (DM). Calibrations for myoglobin, collagen and ash content showed a poor predictability, probably as a consequence of the lack of correlation between these parameters and EE content. However, NIRS technology could be an useful tool for estimating the main chemical parameters of oxen meat samples, thus guaranteeing the standards of quality marks.

Intoxication of sheep with quebracho tannin extract.

This experiment was carried out to study the toxicity of quebracho tannin extract (containing 760 g of condensed tannins [CTs] per kg), with the aim of validating its use as a feed additive for improving the digestive utilization of protein-rich feeds. Four groups (Q(0), Q(1), Q(2) and Q(3)) of four sheep were dosed intra-ruminally once daily, for up to 21 days with, respectively, 0, 0.5, 1.5 or 3.0 g quebracho tannin extract/kg live-weight (LW). Feed intake, live-weight changes, plasma biochemistry, indicators of hepatic detoxification function, gross lesions and histopathology were examined. Animals in groups Q(0), Q(1) and Q(2) consumed all the offered feed. In contrast, feed intake was practically nil after 6 days of quebracho dosing in group Q(3), this being associated with a loss of 4.7+/-1.30 kg LW in 10 days (P<0.05). Sheep from groups Q(0), Q(1) and Q(2) remained healthy throughout the experiment. Ewes from group Q(3) became weak and depressed on day 5 and after 8 days of dosing remained recumbent. They were humanely killed after 10 days to avoid suffering. In general, neither gross lesions nor microscopical changes were observed in animals from groups Q(0), Q(1) and Q(2). However, Q(3) sheep showed striking lesions in the digestive tract (well-demarcated ulcers filled with necrotic material in the mucosa of the rumen and reticulum, distension of abomasum and small intestine, and dense mucous material in the caecum), and changes in plasma biochemistry. Cytochrome P-450 and glutathione concentrations were significantly reduced in Q(3) sheep (P<0.05). It is concluded that quebracho tannin extract is not toxic for ruminants, except in concentrations too high to be encountered under practical conditions.

An in vitro study on the ability of polyethylene glycol to inhibit the effect of quebracho tannins and tannic acid on rumen fermentation in sheep, goats, cows, and deer

Abstract. Batch cultures of rumen microorganisms, using rumen fluids from 4 ruminant species, sheep, goats, cows, and deer, were used to study the ability of polyethylene-glycol (PEG 6000) to inhibit the effect of 2 types of tannins, quebracho (QUE, a condensed tannin) and tannic acid (TA, a hydrolysable tannin) on several in vitro rumen fermentation characteristics. Both QUE and TA were able to impair ruminal fermentation (they reduced gas production, extent of degradation, ammonia-N, and volatile fatty acid concentrations, etc.; P < 0.05), with differences depending on the inoculum donor. The clearest effect of tannins was the reduction of the rates of fermentation, which was observed in all species (P < 0.05). The detrimental effects of tannins were removed by the presence of PEG in most cases, but there were important variations and noticeable exceptions. Thus, for instance, PEG failed to revert the negative effect of TA on the rate of fermentation and the extent of degradation (P < 0.05). The extent of the limited ability of PEG to completely inhibit the negative effects of tannins on in vitro ruminal fermentation seems to depend both on the type of tannin and the species of the rumen inoculum donor.

Effect of tannic acid on rumen degradation and intestinal digestion of treated soya bean meals in sheep

The current experiment was conducted to study the effect of different doses of tannic acid, a hydrolysable tannin, on ruminal degradation and post-ruminal digestion of treated soya bean meals (SBM) in sheep. Samples of SBM were prepared by spraying 100 g SBM with 100 ml distilled water containing 0, 1, 5, 10, 15 or 25 g of commercial tannic acid (So, S TA1 , S TA2 , S TA3 , S TA4 and S TA5 , respectively). Three ruminally cannulated ewes, that had never consumed tannic acid previously, were used to determine in situ degradability of tannic acid-treated SBM. Intestinal digestibility of protein remaining after 16 h rumen incubation was estimated in vitro. Extent of rumen degradation of SBMs was significantly (P < 0.05) affected by the tannic acid treatment. All doses of tannic acid used in this experiment, even the lowest one (S TA1 ), significantly decreased the extent of N degradation but only doses higher than that used to treat S TA3 reduced the extent of DM degradation. This reduction in the extent of DM and N degradation was mainly due to a marked decrease in the immediately degradable fraction (a), which was observed in all treated SBM, and to a lower rate of degradation (c), observed in meals S TA3 , S TA4 and S TA5 , Intestinal digestion of the non-degraded protein was decreased (P < 0.05) by treatment with the two highest doses of tannic acid (those used to treat meals S TA4 and S TA5 ). It was therefore concluded that tannic acid can exert a negative effect both on rumen degradation and on intestinal digestion of SBM, this effect being clearly dependent on the dose used to treat the SBM.

Animal performance and chemical body composition of lambs fed diets with different protein supplements

Abstract Thirty six Merino lambs with average initial live weight of 13.5 kg (SE±0.56 kg) were used in a 3×3 factorial arrangement (4 lambs per group). The treatments were three concentrate supplements (barley [B], barley 82.5% plus soybean meal 14.5% [BSM] and barley 82.5% plus meat meal 14.5% [BMM]) and three slaughter weights (20, 25 and 30 kg live weight). The lambs fed the B diet consumed less concentrate supplement (0.701 vs. 0.780b and 0.758b kg DM day −1 , P −1 , P −1 LW gain, P P −1 DM), there were no differences ( P >0.05) in crude protein intake between BSM and BMM. (171.0 vs. 179.7 g crude protein day −1 ). The source of dietary protein (soybean meal vs. meat meal) did not have a significant influence ( P >0.05) on performance and chemical body composition of lambs. The interactions between the effect of slaughter weight and the concentrate supplement were non-significant ( P >0.05). This study suggests that meat meal can successfully replace soybean meal as a protein supplement for growing lambs from weaning to 30 kg live weight and offer an alternative to soybean meal as a regional protein source for lamb diets.

Discrimination of adult steers (oxen) and young cattle ground meat samples by near infrared reflectance spectroscopy (NIRS)

Near infrared reflectance spectroscopy (NIRS) was used to discriminate different types of ground beef samples. Fifty-three and sixty-seven samples of longissimus thoracis muscle corresponding to adult castrated steers (over 4 years old) and young cattle (under 14 months old), respectively, were homogenized and scanned over the NIR range (1100-2500nm). The results showed that NIRS could successfully discriminate 100% of ground beef samples depending on the sort of animal, probably as a consequence of differences in the intramuscular fat and water contents. Thus, NIRS is a fast, inexpensive, and non-destructive method that can be used to discriminate these beef products.

Comparative digestibility and digesta flow kinetics in two breeds of sheep

A study was conducted to compare apparent digestibility and digesta flow kinetics in the whole digestive tract in two breeds of sheep (Churra and Merino) offered alfalfa hay at about maintenance. Ten mature sheep (five Churra and five Merino) each fitted with a rumen cannula were used in the study. Apparent digestibility was determined by total faecal collection. Liquid (Co-EDTA) and solid (Cr-mordanted fibre) markers were used to estimate rumen volumes and digesta flows. There were no significant differences between Churra and Merino sheep either in dry-matter or fibre apparent digestibility (P > 0·05). Liquid and solid passage rates did not differ between breeds and the estimated total mean retention times were similar for both genotypes. The volume of liquid in the rumen was proportionately 0·14 greater in Churra than in Merino sheep, although the difference was not significant. Estimated saliva secretion was greater in Churra (11·6 (s.e. 0·77) I/day) than in Merino sheep (10·5 (s.e. 0·72) I/day) but the difference did not reach statistical significance. Solid contents of the rumen did not differ between breeds. Rumen particle density was lowest at 2 h after feeding and remained stable at other sampling times, with no significant differences between breeds. There were no significant differences between breeds in the urinary excretion of total purine derivatives but urinary excretion of allantoin and microbial nitrogen supply tended to be higher in Merino than in Churra sheep ( P

Relationship of body condition score and live weight with body composition in mature Churra ewes

Thirty-five mature Churra ewes, ranging in live weight from 30·3 to 52·6 kg and in body condition score from 1·25 to 4·00 were used to study the relationship between body condition score (BCS), live weight (LW) and body composition and fat distribution in ewes of this breed, which is one of the major sheep breeds of northern Spain. The procedure at slaughter and at subsequent dissection was designed to partition each body into two components, carcass and ‘non-carcass’. Right side carcasses and ‘non-carcass’ components were used to analyse the chemical composition. From the left side of the lumbar region a joint was cut and dissected into muscle, bone, subcutaneous and intermuscular fat. According to the results obtained, omental fat represented the highest proportion of total internal fat regardless of the level of fatness. Distribution of internal fat was similar to that observed in other milk production breeds. Regressions on LW explained more of the variation than those on BCS for individual internal fat depots and chemically determined ‘non-carcass’ fat. The prediction of total body fat afforded by LW was better than that provided by BCS. The subcutaneous and intermuscular fat depots in the lumbar joint were well correlated with BCS, carcass fat and total fat in the body, validating the use of this region for assessing BCS in Churra ewes. Nevertheless, the correlation coefficient with the omental depot was not statistically significant. The results of this study suggest that BCS was not as accurate for estimating body composition and fat depots in mature Churra ewes as has been shown previously in other breeds. The single most effective prediction index was LW. However, the utilization of both BCS and LW together provided more accurate estimations.

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.