Resumen El objetivo del estudio fue comparar el efecto de dispositivos intravaginales liberadores de progesterona natural (CIDR) nuevos y reutilizados en protocolos de 6 días sobre el desempeño reproductivo y en las concentraciones de progesterona en suero sanguíneo de ovejas multíparas. Un total de 172 ovejas con peso corporal promedio de 59 kg se distribuyeron al azar en cuatro tratamientos: CIDR1 (grupo testigo con dispositivos nuevos) y CIDR2, CIDR3, CIDR4 (con 6, 12 y 18 días de uso, respectivamente). En cuanto al inicio de estro, hubo diferencia (P≤0.05) únicamente entre el tratamiento con CIDR nuevos (40 ± 10 h) y CIDR de segundo uso (31 ± 9 h). En las variables presencia de estro, porcentaje de gestación, porcentaje de fertilidad y tipo de parto no se obtuvieron diferencias significativas (P>0.05) entre tratamientos. La presencia de estro osciló entre 93 y 100 %, el valor promedio de gestación fue 80.8 %, 80.2 % para fertilidad y 1.26 para el índice de prolificidad. Los porcentajes de partos sencillos fueron mayores (P≤0.05) a los partos dobles en los cuatro tratamientos. Se concluye que el uso de CIDR en protocolos de 6 días permite que los dispositivos sean utilizados hasta por cuatro ocasiones con buenos resultados.

Abstract Estrus synchronization( is a vital strategy in sheep production and is accomplished most often via controlled internal drug release (CIDR) devices. Reuse of CIDR devices can reduce operating costs and ewe exposure to progesterone (P4), but remains controversial. A comparison was made of the effects of new and reused natural progesterone-releasing intravaginal (CIDR) devices in six-day protocols on reproductive performance variables and blood serum progesterone concentrations in multiparous ewes. A total of 172 sheep (average body weight = 59 kg) were randomly distributed into four treatments: CIDR1 (control group, new devices), CIDR2 (second-use), CIDR3 (third-use) and CIDR4 (fourth-use). The variables ewes in estrus, pregnancy rate, fertility rate and parturition type did not differ (P>0.05) between treatments. Estrus onset was later (P≤0.05) in CIDR1 (40 ± 10 h) than in CIDR2 (31 ± 9 h). Ewes in estrus ranged from 93 to 100 %, average pregnancy rate was 80.8 %, average fertility rate was 80.2 % and the prolificacy index was 1.26. The single delivery rate was higher (P≤0.05) than the double delivery rate in all four treatments. Intravaginal CIDR devices can be used in ewes up to four times in six-day estrus synchronization protocols without affecting reproductive variables.

Resumen El objetivo de este estudio fue determinar el nivel máximo de inclusión de aceite de canola (AC) en dietas para cerdos en finalización, para incrementar el contenido de ácido oleico y ácidos grasos insaturados y mejorar la relación Ω6: Ω3 en la carne, sin afectar el comportamiento productivo, características de la canal y fisicoquímicas de la carne. Los tratamientos fueron: la sustitución gradual de aceite de soya (6%) por AC en dietas para cerdos en etapa de finalización I y II (0, 2, 4 y 6% de AC). Las unidades experimentales fueron 48 cerdos machos castrados con peso vivo inicial de 50.00 ± 4.5 kg, evaluados durante cuatro semanas en cada etapa. Con los datos obtenidos se realizó un ANDEVA y se detectaron tendencias lineales o cuadráticas (P≤0.10). En finalización I la ganancia de peso disminuyó con la inclusión de 2% de AC, aunque la incorporación de 2 y 4% de AC no tuvo efecto. En finalización II, un nivel entre 2-4% de AC redujo el consumo de alimento y mejoró la conversión alimenticia (P≤0.05). La adición de AC no modificó las características de la canal y no afectó las características fisicoquímicas de la carne (P≥0.10). El AC en la dieta aumentó la concentración de ácidos grasos monoinsaturados (AGMI) y ácido oleico (P≤0.05); redujo el ácido linoleico (P≤0.03), ácidos grasos poliinsaturados (P≤0.07) y la relación Ω6:Ω3 (P≤0.01). En conclusión, la adición de AC (2-6%) en la dieta de cerdos en finalización incrementa gradualmente el contenido de ácido oleico y de AGMI, además, mejora la relación Ω6:Ω3 en la carne de cerdo, sin afectar las variables productivas y la calidad de la carne.

Abstract The objective of this study was to determine the maximum level of inclusion of canola oil (CO) in diets for finishing pigs, to increase the content of oleic acid and unsaturated fatty acids and improve the Ω6:Ω3 ratio in meat, without affecting the productive performance, carcass characteristics and physicochemical characteristics of the meat. The treatments were: the gradual substitution of soybean oil (6 %) for CO in diets for pigs at finishing stage I and II (0, 2, 4 and 6 % of CO). The experimental units were 48 castrated pigs with initial live weight of 50.00 ± 4.5 kg, evaluated for four weeks at each stage. With the data obtained, an ANOVA was performed, and linear or quadratic trends were detected (P≤0.10). At finishing stage I, the average daily gain decreased with the inclusion of 2 % of CO, although the incorporation of 2 and 4 % of CO had no effect. At finishing stage II, a level between 2-4 % of CO reduced average daily feed intake and improved feed conversion (P≤0.05). The addition of CO did not modify the characteristics of the carcass and did not affect the physicochemical characteristics of the meat (P≥0.10). CO in the diet increased the concentration of monounsaturated fatty acids (MUFAs) and oleic acid (P≤0.05); it reduced linoleic acid (P≤0.03), polyunsaturated fatty acids (P≤0.07) and the Ω6:Ω3 ratio (P≤0.01). In conclusion, the addition of CO (2-6 %) in the diet of finishing pigs gradually increases the content of oleic acid and MUFAs, in addition, it improves the Ω6:Ω3 ratio in pork, without affecting the productive variables and the quality of the meat.

Abstract: The objective of this research was to determine the optimum concentration of synthetic arginine (Arg) that should be added to diets of nursery pigs to improve the productive performance. The addition of five concentrations of synthetic Arg (0.0, 0.5, 1.0, 1.5 and 2.0%) in diets was evaluated with 40 hybrid (Yorkshire × Duroc × Pietrain) barrows, with average initial live weight of 8.72 ± 1.36 kg and 30 days of age. The design used was completely randomized with five treatments and eight repetitions. The data were analyzed with ANOVA and treatment means were compared with Tukey’s test (p ≤ 0.05). The addition of 0.5% Arg in the diet improved average daily feed intake, average daily gain and gain: feed ratio (p < 0.05). The plasma urea concentration increased with the addition of 2% Arg in the diet (p < 0.05).

Resúmen: El objetivo de esta investigación fue determinar la concentración óptima de arginina (Arg) sintética que se debe adicionar a dietas para cerdos en iniciación para mejorar el comportamiento productivo. En el experimento se evaluó la adición de cinco concentraciones de Arg sintética (0.0, 0.5, 1.0, 1.5 y 2.0%), con 40 cerdos híbridos castrados, con peso inicial promedio de 8.72 ± 1.36 kg y 30 días de edad. El diseño utilizado fue completamente al azar con cinco tratamientos. Los datos se analizaron con ANOVA y las medias de tratamientos se compararon con la prueba de Tukey (p ≤ 0.05). La adición a partir de 0.5% de Arg en la dieta mejoró el consumo de alimento, la ganancia de peso y la conversión alimenticia (p < 0.05). La concentración de urea en plasma se incrementó con la adición de 2% de Arg en la dieta (p < 0.05).

ABSTRACT An experiment was carried out to evaluate the effect of an herbal choline feed plant additive on the productive parameters and blood metabolites of finishing lambs. Forty male Hampshire × Suffolk lambs (initial body weight of 30.36±3.75 kg) were assigned according to a completely randomized design. Treatments consisted of dietary inclusion of the herbal additive BioCholine at 0, 3, 6, and 9 g/kg dry matter for 56 days. A linear response for herbal choline dose was observed for daily gain, final body weight, feed conversion, blood glucose, and blood phosphatidylcholine as herbal choline level was increased in the diet. Total protein, globulins, and low-density lipoproteins showed a quadratic effect, and there were no effects on intake, Longissimus dorsi area, back fat, blood cholesterol, triglycerides, high-density lipoproteins, or albumins. The inclusion of the herbal choline feed plant additive improved daily gain and feed efficiency of finishing lambs. The choline feed plant additive is a source that can be used to meet choline requirements in small ruminants, as demonstrated by blood phosphatidylcholine and lamb performance.

Abstract The objective was to evaluate the addition of xylanase in nursery pig diets with a high amount of wheat bran (WB) and two energy levels. Growth performance, carcass characteristics and plasma urea concentration were assessed. Forty-eight hybrid barrows were used (7.98 kg initial body weight and 28 d of age), allotted in a completely randomized design. Treatments (T) were: T1, control diet: 3350 Kcal; T2: 3275 Kcal + xylanase; T3: 3350 Kcal + xylanase; T4: 3350 Kcal + WB + xylanase; T5: 3275 Kcal + WB + xylanase; T6: 3350 + WB + xylanase. The variables were analyzed with ANOVA and treatment means were compared with Tukey's test (p ≤ 0.1). For average daily gain (ADG), average daily feed intake, final body weight and fat free lean gain (FFLG), better response was observed in pigs fed diets without WB (p ≤ 0.1) where xylanase compensated energy reduction. The inclusion of xylanase in WB diets reduced the ADG and final body weight (p ≤ 0.1). Supplementation with WB did not change backfat thickness, longissimus muscle area (LMA) and lean meat percentage (p > 0.1). The backfat thickness and LMA were not affected (p > 0.1) by reducing energy in diets without WB (p > 0.1). In conclusion, diets high in wheat bran content affect growth performance variables, but it is offset by the addition of xylanase, as long as the energy matrix is observed.

Resumen El objetivo fue evaluar la adición de xilanasas en dietas con alta cantidad de salvado de trigo (ST) y dos niveles de energía para cerdos en iniciación sobre la respuesta productiva, características de la canal y concentración de urea en plasma. Se utilizaron 48 cerdos híbridos castrados de 7.98 kg de peso inicial y 28 d de edad, distribuidos en un diseño completamente al azar. Los tratamientos (T) fueron: T1, dieta testigo: 3350 Kcal de EM kg-1; T2: 3275 Kcal de EM kg-1 + xilanasas; T3: 3350 Kcal de EM kg-1+ xilanasas; T4: 3350 Kcal de EM kg-1+ ST + xilanasas; T5: 3275 Kcal de EM kg-1+ ST + xilanasas; T6: 3350 de EM kg-1+ ST + xilanasas. Los datos se analizaron con ANOVA, las medias de los tratamientos se compararon con la prueba de Tukey (p ≤ 0.1). Para la ganancia de peso (GDP), consumo de alimento, peso final (PVF) y ganancia de carne magra (GCM) se observó mejor respuesta en cerdos alimentados sin ST (p ≤ 0.1); compensando las xilanasas la reducción de energía. La inclusión de xilanasas en dietas con ST redujo la GDP y el pVF (p ≤ 0.1). La inclusión de ST no modificó la grasa dorsal (GD), área del músculo longissimus (AML) y GCM (p > 0.1). La GD y AML no fueron afectadas al reducir la energía en las dietas sin ST (p > 0.1). Las dietas con alto contenido de salvado de trigo afectan las variables productivas; aunque se compensa con la adición de xilanasas mientras se respete la matriz energética.

The objective was to evaluate two levels of lysine and threonine for growing pigs on growth performance, carcass characteristics and plasma urea concentration. In experiment 1, 36 pigs were used with initial body weight of 27.65 ± 5.65 kg during four weeks, allotted in a completely randomized design with a factorial arrangement 2 (lysine: 0.83 and 0.93 %) with x 2 (threonine: 05.52 and 0.62 %). The variables were analized ANOVA and treatment means were compared with Tukey's test. There was not effect on the concentration of lysine and threonine in all variables (p > 0.05). In experiment 2, 35 pigs were used with initial body weight of 16.71 ± 7.85 kg during six weeks, were evaluated five levels of threonine (0.52, 0.62, 0.72, 0.82 and 0.92 %), distributed in a completely randomized design. Orthogonal contrasts were used to determine linear, quadratic and cubic effects to estimate the optimal biological level (OBL) for each variable. The NOB for average daily gain and feed consumption was 0.90 % digestible threonine. In experiment 1 and 2 the concentration of urea in plasma was modified by the amount of lysine and threonine in the diet (p < 0.05). We conclude that the most appropriate level of digestible lysine to diet is 0.83 % and 0.90 % digestible threonine.

El objetivo del trabajo fue evaluar dos niveles de lisina y treonina digestibles en cerdos en crecimiento, para analizar el comportamiento productivo, características de la canal y la concentración de urea en plasma. En el experimento 1 se utilizaron 36 cerdos con peso promedio inicial de 27.65 ± 5.65 kg durante cuatro semanas, distribuidos en un diseño completamente al azar con arreglo factorial 2x2, dos concentraciones de lisina: 0.83 y 0.93 % y treonina: 05.52 y 0.62 %, respectivamente. Con los datos se realizó un ANOVA y las medias de los tratamientos se compararon con la prueba de Tukey. No hubo efecto por la concentración de lisina y treonina en las variables (p > 0.05). En el experimento 2 se utilizaron 35 cerdos con peso promedio inicial de 16.71 ± 7.85 kg durante seis semanas para evaluar cinco niveles de treonina (0.52, 0.62, 0.72, 0.82 y 0.92 %), en un diseño completamente al azar. Se utilizaron contrastes ortogonales para detectar efectos lineales, cuadráticos y cúbicos para determinar el nivel óptimo biológico (NOB) para cada variable. El NOB para ganancia de peso y consumo de alimento fue 0.90 % de treonina digestible. En el experimento 1 y 2 la concentración de urea en plasma se modificó por la cantidad de lisina y treonina presentes en la dieta (p < 0.05). Se concluye que el nivel más adecuado de lisina digestible para dietas es de 0.83 % y de treonina digestible de 0.90 %.

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 (Yorkshire×Landrace×Duroc) barrows (17.3-83.5 kg), which were individually penned and allotted in a completely randomized design in a factorial (2×3) arrangement for 84 d. The analysis by phases indicated that CP level affected some variables. Average daily gain, average daily feed intake, fat free lean gain, backfat thickness, longissimus muscle area and final body weight were reduced (P≤0.05) feeding the lowest CP diet in nursery and growing pigs. Plasma urea nitrogen concentration was also lower (P≤0.05) in the growing and finishing phases when fed the lowest CP level. The global analysis showed that all the analyzed variables (except feed gain ratio, lean meat percentage and plasma urea nitrogen concentration) were reduced (P≤0.05) in the pigs fed low-protein diets; plasma urea nitrogen concentration tended to be lower (P=0.07) when CP was reduced. The fatty acid profile of the meat (semimembranosus and longissimus muscles) indicated that CLA addition increased CLA isomers and total saturated fatty acids, and reduced the total monounsaturated fatty acids (P≤0.05). α-Linolenic acid was lowered in longissimus muscle of pigs fed LPD (P=0.08). These results indicated that reducing the crude protein concentration in the diet of fattening pigs from 20.5 to 16.0% in nursery phase; from 16.0 to 14.5% in growing stage; and from 14.0 to 12.5% in finishing pigs, did not negatively affect the growth performance, nor carcass characteristics. The results also showed that the addition of CLA did not improve pig response and the concentration of unsaturated fatty acids and total lipids altered the feeding LPD.

An experiment was conducted to evaluate levels of calcium (Ca) and available phosphorus (AP) in hens. For this study 300 Leghorn Hy-line W36 hens were used. Five treatments were evaluated, level of Ca and AP in the diet: T1, 4.34 and 0.18%; T2, 4.34 and 0.23%; T3, 4.62 and 0.18%; T4, 4.62 and 0.23% and T5, 3.25 and 0.25% (control). The experiment lasted 48 wk. It was measured feed, Ca and AP consumption, number of eggs, egg mass, feed conversion, egg weight, specific gravity and percentage of eggshell. In feed consumption, number of eggs, egg mass, feed conversion and egg weight, there were no differences among treatments (P>0.05). Higher consumption of calcium (P<0.05) was observed in the hens of T3 and T4 (4.80 and 4.81 g-1 hen-1); in consumption of available phosphorus the hens of T5 consumed more (P<0.05) than the others (0.258 g-1 hen-1). For specific gravity with T1, T3 and T4 (1.0837, 1.0834 and 1.0841) there were better results (P<0.05). In percentage of eggshell were observed better results for T1, T2, T3 y T4 (P<0.05). It is concluded that the concentration of Ca and Pd suggested by the NRC (1994) are not sufficient for maximum eggshell quality.

Se realizó un experimento para evaluar niveles de calcio (Ca) y fósforo disponible (Pd) en gallinas. Se utilizaron 300 gallinas Leghorn Hy-line W36 y se alimentaron con cinco tratamientos, tomando en cuenta los niveles óptimos de encontrados en la literatura. Las dietas fueron: T1, 4.34% Ca y 0.18% Pd; T2, 4.34% Ca y 0.23% Pd; T3, 4.62% Ca y 0.18% Pd; T4, 4.62% Ca y 0.23% Pd y T5, 3.25% Ca y 0.25% Pd. Se midió consumo de alimento, consumo de Ca y de Pd, conversión alimenticia, número de huevos, masa de huevo, peso del huevo, gravedad específica y porcentaje de cascarón. Para número de huevos, masa de huevo, consumo de alimento, conversión alimenticia y peso de huevo, no se encontraron diferencias entre tratamientos (P>0.05). Se observó mayor consumo de Ca (P<0.05) en las gallinas de los tratamientos T3 y T4 (4.80 y 4.81 g ave-1 día-1); en cuanto a consumo de fósforo disponible, las gallinas del T5 consumieron más (P<0.05) que las demás (0.258 g ave-1 día-1). Para gravedad específica, hubo mejores resultados con T1, T3 y T4 (1.0837, 1.0841, y 1.0840; P<0.05). En porcentaje de cascarón se observaron mejores resultados con las gallinas de T1, T2, T3 y T4 (P<0.05). Se concluye que las concentraciones de Ca sugeridas por el NRC (1994), no son suficientes para máxima calidad del cascarón; sin embargo, los niveles de Pd 0.18 y 0.23% son menores a los sugeridos por el NRC, de 0.25%.

The dietary crude protein (CP) can be reduced by four percentage units when corn-soybean meal (SBM) and crystalline amino acids (AA) are used to formulate diets for growing pigs. With sorghum the results have not been conclusive. Therefore, two experiments were conducted to determine the lowest CP value in sorghum-SBM, AA supplemented diets, using plasma urea nitrogen (PUN), growth performance, and carcass characteristics as the response criteria. In Experiment 1, the percentage of CP in the treatments was as follows: T1) 16.0, control diet; T2) 14.5; T3) 13.0; and T4) 11.5. Eight gilts were used in a cross-over design with four periods of 7 days each. Blood samples were collected the last day of the period to determine PUN. Several regression models were used to obtain the best prediction of PUN. The lowest PUN indicated that CP can be reduced from 16 to 11.5%. The best regression model was the nonlineal exponential, which can predict that the minimum plasma urea concentration is obtained with 10.48% of CP. In Experiment 2, the percentage of CP and metabolizable energy Mcal kg-1) were as follows: T1) 16, 3.265, control; T2) 16, 3.165; T3) 14.5, 3.265; T4) 14.5, 3.165; T5) 11.5, 3.265; and T6) 11.5, 3.165. Thirty barrows were assigned in a completely randomized design with a 3 × 2 factorial arrangement, six treatments and five replicates of one barrow (individually penned) for each treatment. The lowest CP reduced the average daily gain, feed gain ratio, and PUN. The lowest ME reduced the feed gain ratio. These results indicate that reducing CP diminishes PUN, although some productive variables are affected.

La proteína cruda (PC) puede reducirse cuatro unidades porcentuales cuando se utiliza maíz-pasta de soya y aminoácidos (AA) para cerdos en crecimiento. Con sorgo no se han obtenido resultados concluyentes. Por ello se realizaron dos experimentos para determinar el porcentaje mínimo de PC en dietas sorgo-pasta de soya adicionadas con AA, con base en la concentración de urea en plasma de cerdos en crecimiento, y su respuesta productiva. En el Experimento 1, el porcentaje de PC en los tratamientos fue: T1) testigo, 16.0; T2) 14.5; T3) 13.0; y T4) 11.5. Se utilizaron ocho cerdas en un diseño cruzado (cross-over), con cuatro periodos de siete días. El último día de cada periodo se obtuvo sangre para determinar la concentración de urea. Se utilizaron varios modelos de regresión para obtener el que mejor predijera la concentración de urea. El menor nivel de urea indicó que la proteína puede reducirse de 16% hasta 11.5%. El mejor modelo de regresión fue el no lineal exponencial, con el que se puede predecir que la mínima concentración de urea se obtiene con 10.48% de PC. En el Experimento 2, los porcentajes de PC y las Mcal EM kg-1 fueron: T1) testigo, 16, 3.265; T2) 16, 3.165; T3) 14.5, 3.265; T4) 14.5, 3.165; T5) 11.5, 3.265; y T6) 11.5, 3.165, que se proporcionaron a 30 cerdos machos castrados (cinco repeticiones por tratamiento), alojados individualmente, en un diseño completamente al azar con arreglo factorial 3 × 2, con seis tratamientos y cinco repeticiones por tratamiento. La menor PC redujo la GDP, la conversión alimenticia y la urea en plasma. La menor EM redujo la conversión alimenticia. Lo anterior indica que disminuir la proteína reduce la urea en plasma, aunque se afectan algunas variables productivas.