RESUMO
Para conocer el efecto de suplementación con harina de tres arbustivas forrajeras tropicales, en el comportamiento productivo y fermentación ruminal de corderos en crecimiento, se realizó un estudio durante 90 días, utilizando 30 corderos con encaste de Pelibuey y Black Belly (18,29 ± 1,56 kg PV), mantenidos en pastoreo continuo en estrella africana (Cynodon plestostachyus; 75,5% FDN y 6,1% PC) de 7:00 a.m. a 4:00 p.m, posteriormente los animales fueron alojados en corraletas individuales, proporcionándoles 200 g animal-1 d-1 de suplemento de acuerdo a los tratamientos (T) evaluados: T1 = sólo pastoreo (SP), T2 = T1+concentrado comercial (CC), T3 = T1+harina de cocoíte (Gliricidia sepium; HC), T4 = T1+harina de morera (Morus alba; HM) y T5 = T1+harina de tulipán (Hibiscus rosa-sinensis; HT). Las variables registradas fueron: consumo de suplemento y pasto, ganancia diaria de peso (GDP), digestibilidad aparente de materia seca del suplemento y del pasto. En fluido ruminal se midió pH, concentración de ácidos grasos volátiles, nitrógeno amoniacal, bacterias totales y protozoarios. El CC y la HT presentaron el mejor (P < 0,05) consumo de suplemento (CC, 181,6ª; HC, 97,7c; HM, 149,7b; HT, 167,2ab g d-1), de materia seca total (SP, 789,1b; CC, 976,8ª; HT, 941,8ª g d-1) y la mejor GDP (SP, 46,1b; CC, 81,6ª; HT, 77,1ª; g d-1). El CC propició la más alta (P < 0,05) digestibilidad aparente de la materia seca (DAMS, 60,97ª); en contraste la más baja (P < 0,05) DAMS se presentó con el uso de HC (SP, 49,27ab; CC, 54,00ª; HC, 48,52C; HM, 50,47ab; HT, 50,54ab). En las variables ruminales, no se observaron diferencias entre tratamientos para pH, nitrógeno amoniacal y AGV; solamente se registraron cambios (P < 0,05) en la concentración (1 × 10(8) mL-1) de bacterias totales (SP, 45,0ª; HM, 1,1b) y de protozoarios (SP, 20,73b; CC, 96,01ª; 1 × 10(4) mL-1). La harina de tulipán mostró una respuesta similar a la del CC. La menor respuesta se obtuvo con HC. Por lo anterior se recomienda HT como sustituto de CC para corderos en pastoreo en el trópico.
A study was carried out in order to determine the effect of a commercial feed and three different meals produced by tropical forage shrubs, on productive performance, digestibility and some rumen variables, when used as supplements for grazing lambs. Thirty crossbreed (Pelibuey X Black Belly) male lambs (18.29 ± 1.56 Kg BW), were used in a 90 d study. Animals were on continuous grazing of African star (Cynodon plestostachyus; (75.5% NDF, 6.1% CP) from 7:00 am to 4:00 pm. After grazing animals were housed in individual pens and fed (200 g animal-1 d-1)any of four supplements, according to treatment: T1 = grazing (G); T2 = T1 + commercial concentrate (CC); T3 = T1 + cocoite meal (Gliricidia sepium; CM); T4 = T1 + morera meal (Morus alba; MM), and T5 = T1 + tulipan meal (Hibiscus rosa-sinensis; TM). Supplement and forage intake, dry matter digestibility and daily weight gain, were measured. Volatile fatty acids (VFA), ammonia nitrogen concentration, total bacteria and protozoa were determined in rumen liquor. Differences in supplement intake (P < 0.05) (CC, 181.6ª; CM, 97.7c; MM, 149.7b; TM, 167.2ab g d-1), dry matter intake (OG, 789.1b; CC, 976.8ª; TM, 941.8ª g d-1) and daily weight gain (OG, 46.1b; CC, 81.6ª; TM, 77.1ª; g d-1) were found. The highest (P < 0.05) percentage of dry matter digestibility (DMD) was found for CC (CC, 60.97ª). Forage DMD was the lowest for CM (OG, 49.27ab; CC, 54.00ª; CM, 48.52C; MM, 50.47ab; TM, 50.54ab). No differences (P > 0.05) were found for rumen pH, ammonia nitrogen and VFA concentration among treatments. Compared with OG treatment, supplementation with MM decreased (P < 0.05) total bacteria concentration (OG, 45.0ª vs MM, 1.1b × 10(8) mL-1)whilst CC increased protozoa concentration (OG, 20.73b vs CC, 96.01ª × 10(4) mL-1). Supplementation with TM showed similar results that those observed with CC. The lowest response was observed for CM and OG. It is concluded that TM can be used as a supplement instead of CC in the tropic for grazing lambs.