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

To analyze the effect of conjugated linoleic acid (CLA) on the meat of pigs (0,1%) and three crude protein (CP) levels (nursery: 20.5, 16.0, 14.5%; growing: 16, 14.5, 11.5%; and finishing: 14.0, 12.5, 11% CP), studies were conducted with 36 hybrid

The aim of this study was to evaluate the effects of adding conjugated linoleic acid (CLA) to boar diets on semen production and characteristics, the fatty acid profile of spermatozoa, and on testicle and boar carcass parameters. Ten lean-type terminal-line (Yorkshire × Landrace × Pietrain) adult boars were randomly assigned to one of two treatments: (1) a control diet and (2) the same diet with 1 % CLA. The research was conducted in Mexico, and animals were exposed to ambient temperatures between 13.5 and 26.3 °C. Boars were ejaculated twice per week during a 12-week period to examine semen production and characteristics. The results suggest that supplementation of boar diets with CLA did not affect the spermatozoa fatty acid profile, semen volume, sperm concentration, viability, or motility, nor did it cause abnormal sperm morphology. Compared to controls, boars fed a CLA diet had a higher seminal pH and increased backfat thickness. In summary, this study indicates that CLA addition in boar diet does not change the semen characteristics or fatty acid profile of spermatozoa; however, it increases backfat thickness in sexually mature boars.Keywords: Semen quality; Backfat thickness; Testicular characteristics. IntroductionSemen quality, including ejaculate volume, sperm concentration, and percentages of sperm mortality and abnormality, determines the economic value of boars. 1 Polyunsaturated fatty acids (PUFAs), mainly ω-3 and ω-6 acids, are abundant in the plasma membrane of boar spermatozoa 2 and provide the sperm plasma mem- Conjugated Cite this as:Zamora-Zamora V, Figueroa-Velasco JL, Cordero-Mora JL, Nieto-Aquino R, García-Contreras AC, Sánchez-Torres MT, Carrillo-Domínguez S, Martínez-Aispuro JA. Conjugated linoleic acid supplementation does not improve boar semen quality and does not change its fatty acid profile. Veterinaria México OA. 2017;4(3).