Grain grinding size of cereals in complete pelleted diets for growing lambs: Effects on animal performance, carcass and meat quality traits.

The main goal of the present study was to clarify the effects of different grinding particle size of grains (2-mm vs. 6-mm) included in complete pelleted diets (CPD) for fattening lambs on animal performance, carcass and meat quality. Twenty male merino lambs (14.8 kg; n = 10 per group) were fed the corresponding diet ad libitum and slaughtered when they reached 27 kg. No differences were observed in the feed conversion ratio or carcass characteristics. However, lambs fed coarser diets (6 mm) were more efficient with less residual feed intake (-14.0 vs. 15.4 g DM/animal/d; P < .05) than lambs fed the 2 mm CPD. Lambs fed the 6-mm CPD showed higher levels of intramuscular fat and saturated fatty acids. Consequently, increasing the particle size of the grains included in CPD allows for improving feed efficiency and intramuscular fat in fattening lambs.

Assessment of the antioxidant effect of astaxanthin in fresh, frozen and cooked lamb patties.

Astaxanthin is a natural red carotene exerting a strong antioxidant action. The effect of this carotene on the oxidative stability of raw and cooked lamb patties was evaluated. Seven experimental treatments were included in this study depending on the antioxidants added, which are: no antioxidant added (control), 450 mg/kg of sodium metabisulphite, 500 mg/kg of sodium ascorbate, and 20 mg/kg, 40 mg/kg, 60 mg/kg and 80 mg/kg of astaxanthin. The raw patties were either refrigerated for up to 11 days or frozen for 3 months under aerobic conditions. Changes in thiobarbituric reactive substances (TBARS), instrumental colour, pH and Eh were determined in the refrigerated patties and TBARS in the frozen patties. Volatile compounds were determined in cooked patties and cholesterol oxides in both cooked and after cooking microwave reheated patties. The changes in TBARS of cooked patties during a four-day refrigerated storage were also studied. Compared to the control patties, the use of astaxanthin reduced the TBARS generation in a manner depending on the dose for both raw and cooked patties during storage (P < 0.05). Astaxanthin added at levels of 60 and/or 80 mg/kg showed a greater antioxidant effect than ascorbate and metabisulphite. The presence of astaxanthin, like that of ascorbate, decreased the oxysterols levels of cooked patties with regard to controls. The amount of volatiles released from the cooked patties was also reduced by astaxanthin. This effect was not observed for ascorbate or metabisulphite. Astaxanthin in lamb patties at levels of 60-80 mg/kg could improve raw and cooked lamb patty oxidative stability during refrigerated aerobic storage, protect their lipids against thermal degradation more than ascorbate and metabisulphite, and reduce oxysterols formation during cooking in a similar way to ascorbate.

Carcass and meat quality characteristics of Churra and Assaf suckling lambs.

Suckling lamb meat is traditionally produced in Mediterranean Europe. Breed can affect the quality of the lamb carcass and meat. This study is aimed at comparing the carcass and meat quality between suckling lambs from a local and a non-native dairy breed, Churra and Assaf. Churra is included in the Spanish Protected Geographical Indication (PGI) 'Lechazo de Castilla y León', whereas Assaf is not. However, Assaf breeders have requested the inclusion of the breed in the PGI. Carcasses and meat from 16 male lambs (eight Churra and eight Assaf) were used in this study. The lambs were all raised under an intensive rearing system and fed on a milk substitute to minimise maternal influence. The carcasses were evaluated for conformation, fatness, joint and leg tissue proportions and the meat was analysed for composition (i.e. proximate composition, iron, haematin, fatty acids and volatiles) and technological quality traits (i.e. texture, water holding capacity, colour and lipid stability). Churra carcasses were larger than Assaf carcasses. However, the proportions of commercial joints and main tissues did not differ between breeds. Cavity and intermuscular leg fat, but not total leg fat, were higher in Churra carcasses. Churra meat showed a higher proportion of n-6 fatty acids, higher redness and better colour stability during aerobic storage. In contrast, Assaf lamb was more resistant to lipid oxidation after cooking. This is a preliminary study to measure the influence of breed on a wide range of quality characteristics in Churra and Assaf suckling lamb carcass and meat. It may be of relevance for breeders, consumers and food policy makers, setting the basis for future studies that include larger commercial populations.