Choline is an essential nutrient for animals, but dietary choline is degraded in the rumen, and thus, should be offered as rumen-protected choline (RPC) in ruminants. In this article, we investigate the effect of RPC supplementation in feedlot lambs. Forty intact male Saint Croix lambs (average: 20.3 kg, 3–4 months of age) on a high grain-low roughage base feed were randomly assigned to four treatments (0, 0.1, 0.2, and 0.3% RPC on dry-matter basis; n = 10 per group). RPC was offered for 90 days after 15 days of adaptation. RPC supplementation was not associated with significant differences in dry matter intake, weight gain, gain:feed ratio, carcass weights, and the dressing percentages. There was a linear decrease in height to the shoulder (p = 0.013) and longissimus muscle area (p = 0.051) with higher RPC levels, and a higher backfat thickness and yield grade with 0.3% RPC compared to 0.1% RPC (p < 0.05). Blood triglycerides concentrations were higher in control (0% RPC) compared to 0.3% RPC (p = 0.008). The lack of significant effects on growth performance and the results on backfat thickness and yield grade, may indicate undesirable effects associated with RPC supplementation. More research is needed to establish the needs and specific quantities of RPC supplementation in feedlot lambs.

Thirty six Landrace × Yorkshire barrows with 18.6 kg of initial body weight were used to evaluate three sources of fatty acids: crude soybean oil, conjugated linoleic acid (CLA), and soybean soapstock in standard crude protein (CP) and low-protein diets for starter (21 d; 205, 160 g kg -1 CP), growing (28 d; 160, 145 g kg -1 CP), and finishing (29 d; 140, 125 g kg -1 CP) phases. Growth performance, carcass characteristics, plasma urea nitrogen concentration and fatty acid profile in meat were evaluated. The reduction of CP diminished average daily gain, feed:gain ratio, longissimus muscle area and plasma urea nitrogen concentration in nursery pigs; reduced longissimus muscle area and plasma urea nitrogen concentration in growing pigs; increased average daily feed intake, and reduced lean meat percentage and plasma urea nitrogen content in finishing pigs. It also increased c9, t11 and c11, t9 CLA isomers and total lipids and lowered eicosapentaenoic and docosahexaenoic acids concentrations in semimembranosus muscle; linolenic acid decreased with low-protein diets in longissimus and semimembranosus muscles; the oil type affected the concentration of c9, t11 and c11, t9 CLA isomers and total saturated fatty acids in semimembranosus muscle; CLA increased individually and total saturated fatty acids, reduced linoleic and docosapentaenoic acids, and increased total lipids in longissimus muscle. These results indicate that decreasing CP changes the profile of fatty acids. The soybean soapstock can replace crude soybean oil in pig diets; while conjugated linoleic acid does not improve response of pigs fed standard-or low-protein diets.Additional key words: feed additives; feeding management; pork meat quality. ResumenEfecto de la fuente de ácidos grasos sobre la respuesta productiva, características de la canal, concentración de urea en plasma y perfil de ácidos grasos en carne de cerdos alimentados con dietas estándar o con baja proteína Se utilizaron 36 cerdos machos castrados (18,6 ± 2,3 kg peso inicial) para evaluar tres fuentes de ácidos grasos: aceite crudo de soya, ácido linoleico conjugado (ALC) y aceite de soya acidulado en dietas estándar en proteína bruta (PB) y con baja proteína para iniciación (21 d; 205, 160 g kg -1 PC), crecimiento (28 d; 160, 145 g kg -1 PC), y finalización (29 d; 140, 125 g kg -1 PC). Se evaluó la respuesta productiva, características de la canal, urea en plasma y perfil de ácidos grasos en carne. La reducción de PB disminuyó la ganancia de peso, conversión alimenticia, área del mús-culo longissimus y urea en plasma en iniciación; redujo el área del músculo longissimus y urea en plasma durante el crecimiento; aumentó el consumo, disminuyó el porcentaje de carne magra y la urea en plasma en finalización. También

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The purpose of this study was to determine how feeding sheep coffee pulp affects carcass characteristics and what changes occur in physicochemical, antioxidant capacity and oxidation of the meat during refrigerated storage. The experiment was carried out in 15 Blackbelly lambs weighing an average 22.86±0.76kg. The animals were assigned to three treatments: T0=control diet, T1=diet with 8% coffee pulp, and T2=diet with 16% coffee pulp. After fattening for 56 days, the sheep were slaughtered and the carcasses assessed. The inclusion of 16% coffee pulp in the diet increased carcass dressing from 48.19 to 50.83% and decreased the amount of fat in rumen and intestines from 3.43 to 2.53% (P<0.05). The inclusion of coffee pulp in the diet did not alter the amount of crude protein or fat in meat or its oxidation and antioxidant capacity during refrigerated storage. However, the inclusion of coffee pulp in the diet decreased fat in the rumen and intestines, and thus increased the amount of usable meat.

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