Maternal and direct dietary polyphenol supplementation affect growth, carcass and meat quality of sheep and goats.

The beneficial effects of polyphenol intake such as improved nitrogen retention make them interesting feed supplements for ruminants. In contrast, dietary polyphenols may have adverse effects on the bioavailability of nutrients and palatability of the feed which might impair growth performance. The beneficial and adverse effects might differ between different ruminant species as well as between direct intake and intake of polyphenol metabolites via suckling when supplemented to lactating dams. This study investigated the effects of maternal and direct polyphenol supplementation via grape seed extract in sheep and goats on growth, slaughter performance, meat quality and fatty acid profile. The diet of lactating East Friesian Dairy sheep (n = 11) and Saanen goats (n = 9) and of their lambs (n = 16) and kids (n = 13), respectively, was supplemented either with grape seed extract (dams: 7.4% and offspring: 5.6%, P) or without (C). This resulted in four groups per species, namely maternalC/offspringC, maternalC/offspringP, maternalP/offspringC, and maternalP/offspringP. In lambs but not in goats, maternalP increased average daily gain and improved slaughter performance whereas offspringP had no effect. Maternal and offspring diet did not affect physicochemical meat quality in lambs, but direct intake of grape seed extract increased rancid aroma of burger patties. In goat kids, both maternal and offspring diets slightly affected meat colour. While groups of meat fatty acids (FAs) were not affected by diet in both species, maternalP in lambs as well as maternalP and offspringP in goat kids increased the meat n-6 to n-3 FA ratio compared to the respective control groups. In goat kid but not in lamb meat, direct intake of polyphenols affected the proportions of several rumen biohydrogenation intermediates. In conclusion, grape seed extract can be applied in both the maternal and offspring diets in sheep and goats while maintaining or even improving offspring growth performance and carcass quality. Only few species-specific effects of grape seed extract supplementation were observed, and additive effects were scarce. Larger studies are required to confirm the observed species-specific growth response to maternalP during lactation. The underlying reasons for this differential response need to be further evaluated.

Pre-slaughter stress and horn status influence physiology and meat quality of young bulls.

The study used 81 young bulls, half of which were disbudded at 7 weeks of age. The effects of horn status during rearing and of acute physical and emotional stress just before slaughter on the physiological status at slaughter and subsequent meat quality were investigated. Bulls were reared in groups containing i) only bulls with horns, ii) only bulls without horns, or iii) mixed (half with, and half without horns). Bulls of each rearing condition were assigned to one of two slaughter conditions: with limited (LS) or with supplementary stress (SS). LS resulted in lower heart rates, stress hormone concentrations and carcass temperature, whereas SS resulted in faster post mortem pH decline and lower juiciness. Horned bulls from unmixed rearing groups had lower early pm temperature, shorter sarcomeres, and lower tenderness compared to disbudded bulls. Correlations and regression analysis revealed relationships between physiological indicators, mainly heart rate before slaughter, and meat quality, including water-holding capacity and indicators of proteolysis.

Replacing sunflower oil by rumen-protected fish oil has only minor effects on the physico-chemical and sensory quality of Angus beef and beef patties.

In the present study, the effects of feeding 450 g/day of rumen-protected fish oil (FO) compared to sunflower oil (SO) to Angus heifers (60 g/kg total intake) were quantified. Animal performance was not affected whereas the physico-chemical meat quality, assessed in three muscles, was slightly affected by diet. The oxidative shelf life of the perirenal fat declined with FO compared to SO. Despite the formerly shown increased n-3 fatty acid proportions of meat due to FO supplementation, a trained sensory panel identified an only slightly more intense fishy flavour in grilled steaks and beef patties from the FO compared to the SO group. In FO compared to SO patties, flavour intensity was more pronounced. The perception of off-flavours was negligible and differences between muscles were larger than between diets. In conclusion, supplementing ruminants with FO containing nutritionally beneficial n-3 fatty acids results in few side-effects on meat quality, restricted to quite faint off-flavours and a shorter fat shelf life.