3 results
Tannin-rich sainfoin pellet supplementation reduces fat volatile indoles content and delays digestive parasitism in lambs grazing alfalfa
- D. Rivaroli, A. Prunier, K. Meteau, I. N. do Prado, S. Prache
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Lambs grazing alfalfa or white clover are prone to flavour taint which can be an impediment to consumer acceptance. Here we investigated whether condensed tannin (CT)-rich sainfoin pellet supplementation of lambs grazing alfalfa influences meat sensory quality. Using three groups of 18 male Romane weaned lambs, we compared three feeding regimes: alfalfa grazing (AF), alfalfa grazing + daily supplementation with CT-rich sainfoin pellets (15 g dry matter (DM)/kg live weight, AS) and stall feeding with concentrate and grass hay indoors (SI). We also investigated the potential interest of sainfoin pellet supplementation for controlling digestive parasitism. The sainfoin pellets contained 42 g of CT/kg of DM and they represented on average 36% of the diet in AS lambs. Skatole and indole were detected in most of the AF and AS lambs, whereas in very few SI lambs. Skatole and indole concentrations in perirenal and dorsal fat were lower in the AS lambs than the AF lambs (P < 0.025 to P < 0.001), but the intensity of ‘animal’ odour and ‘animal’ flavour of the chops did not differ between both forage-grazing groups. Longissimus thoracis et lumborum muscle lightness was lower in the AF and AS lambs than the SI lambs (P < 0.001) with the other muscle colour coordinates being unaffected by the treatment and between-treatment group differences in muscle colour coordinates remaining constant throughout the 9-day display period. Subcutaneous fat colour coordinates were not influenced by the treatment. The number of individual anthelmintic drenches necessary to keep nematode faecal egg count below a threshold of 550 eggs/g of faeces was lower in the AS than the AF lambs (0.94 per lamb v. 1.63 per lamb; P < 0.001). Faecal oocyst count was lower in the AS than the AF lambs for the first measurement made 56 days after the beginning of the experiment (P < 0.001) and was not significantly different between both forage-grazing groups thereafter. The use of CT-rich sainfoin pellets to supplement lambs that are concurrently grazing alfalfa reduced fat volatile skatole and indole concentrations and delayed the onset of both helminth and coccidian infections.
How does barley supplementation in lambs grazing alfalfa affect meat sensory quality and authentication?
- T. Devincenzi, A. Prunier, K. Meteau, S. Prache
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Excessive flavour in lamb meat is undesirable for consumers and can prompt purchase resistance. Volatile indoles responsible for off-flavours accumulate more in the fat of lambs on pasture than on grain and are enhanced when lambs graze alfalfa. Here, we investigated whether barley supplementation of lambs grazing alfalfa influences meat sensory quality. Using three groups of 12 male Romane lambs, we compared three feeding regimes: alfalfa grazing (AG), alfalfa grazing + daily supplementation with barley (29 g/kg live weight0.75, AGS) and stall feeding with concentrate and hay (SF). As some of the compounds involved in meat sensory traits may act as dietary biomarkers, we also investigated potential implications for meat authentication. Although barley represented 38% of the diet in AGS lambs, it did not offer any advantage for animal average daily gain or parasitism level. Animal performance, carcass weight and fatness did not differ between feeding regimes. Dorsal fat firmness tended to be greater in AG than AGS and greater in AGS than SF. Skatole and indole concentrations in perirenal and dorsal fat were lower in SF lambs than in AG and AGS lambs (P<0.01 to P<0.0001), but did not differ between AG and AGS lambs. Yellowness, chroma and hue angle of perirenal fat were lower in SF lambs than in AG and AGS lambs (P<0.001), but did not differ between AG and AGS lambs. Absolute value of the mean integral for both perirenal fat and subcutaneous caudal fat (AVMIPF and AVMISC), quantifying the intensity of light absorption by carotenoids in perirenal and subcutaneous caudal fat, respectively, were lower in SF lambs than in AG and AGS lambs (P<0.0001 for both comparisons), but did not differ between AG and AGS lambs. Meat colour was unaffected by the treatment. We confirm that lambs grazing alfalfa accumulate high levels of volatile indoles in their fat, but we show that barley supplementation to lambs grazing alfalfa is not effective in reducing fat volatile indoles concentration and excessive odour/flavour in the meat. We also confirm that both perirenal fat skatole concentration and AVMIPF are of interest for discriminating lambs that grazed alfalfa from lambs that were stall-fed, and we show that they are not effective for discriminating supplemented from non-supplemented grazing lambs.
Influence of production system in local and conventional pig breeds on stress indicators at slaughter, muscle and meat traits and pork eating quality
- B. Lebret, P. Ecolan, N. Bonhomme, K. Méteau, A. Prunier
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Sensory quality of pork is a complex phenotype determined by interactions between genetic and environmental factors. This study aimed at describing the respective influences of breed and production system on the development of pork quality. Plasma stress indicators and Longissimus muscle (LM) composition, physicochemical and sensory quality traits were determined in two contrasted breeds – the conventional Large White (LW, n=40) and the French local Basque (B, n=60). Pigs were reared in either a conventional (C; n=20 per breed), alternative (A; sawdust bedding and outdoor area, n=20 per breed) or extensive system (E; free-range, n=20 B). All the pigs from A and C systems were slaughtered at the same slaughterhouse, whereas B pigs from the E system were slaughtered at a local commercial abattoir. Major breed differences were found for almost all traits under study. LM from B pigs exhibited higher lipid, lower water and collagen concentrations, as well as lower collagen thermal solubility (P<0.001). Although plasma stress indicators at slaughter did not differ between breeds, except lower (P<0.05) lactate levels in B pigs, they exhibited higher LM pH1 and pHu values, and lower meat lightness, hue angle, water (drip, thawing and cooking) losses, glycolytic potential and shear force. Sensory analyses highlighted higher redness, marbling, tenderness, juiciness and flavour scores (P<0.01) of meat from B compared with LW pigs. Within both LW and B breeds, compared with C, the A system did not (P>0.05) influence plasma stress indicators, LM chemical composition and physicochemical or sensory traits of pork. In contrast, within the B pigs, the E system affected the meat quality more. Lower plasma cortisol levels (P<0.05), but higher plasma lactate, creatine kinase and lactate dehydrogenase activities, and more skin lesions (P<0.05), indicating higher muscular activity during pre-slaughter handling, were found in pigs produced in the E compared with the C system. E pigs exhibited higher meat pH1 and pHu values and shear force (P<0.01) and exhibited lower lightness, hue angle and drip and thawing losses (P<0.01) compared with the C pigs, whereas LM lipid, protein or collagen concentrations were not affected. Regarding sensory traits, the E system produced redder meat, but did not impact the eating quality of pork. Altogether, this study demonstrates that differences in meat quality between B and LW breeds can be modulated by extensive pig production system.