Effect of a controlled-release urea supplementation on feed intake, digestibility, nitrogen balance and ruminal kinetics of sheep fed low quality tropical forage.

Four ruminally cannulated crossbred sheep (25+/-3.4kg BW) were divided into a 4x4 Latin square design to measure the effects of controlled-release urea supplement (CRUS). The basal diet consisted of 60% sugar cane tops (Saccharum officinarum), 30% full plant corn stubble (Zea mays), and 10% King grass (Pennisetum purpureum). Feed intake, digestibility, N balance and in situ ruminal kinetics were studied with four diets, D1 (control), D2, D3 and D4, which included the ratios of 100:0%, 90:10%, 80:20% or 70:30% of basal diet with CRUS. Results showed DMI differences (P<0.05) for D4 (822g per day) versus D1, D2 and D3 (580, 659 and 700g per day, respectively). N retention increased (P<0.05) for D4 (35.69g per day) versus D1, D2 and D3 (9.29, 6.85 and 19.10g per day, respectively). In vivo N digestibility was greater (P<0.05) in D4 (79.63%) than in D1 (57.57%). In vivo digestibility of DM, OM, GE, cellulose and hemicellulose was similar among the four groups. Digestibility of cell walls in D4 was higher (P<0.05) at 74.06% versus 67.78% in D1. In situ DM digestibility showed differences (P<0.05) among all diets at 9, 12, 24 and 48h of incubation. Potentially digestible fiber, 52.61%, was higher (P<0.05) in D4 versus 31.00% in D1. Indigestible fiber, 35.29%, was lowest (P<0.05) in D4 compared to 81.51% in D1. Digestion rate constant (k(d)) was different (P<0.05) between the experimental diets and control. Passage constant (k(p)) was different (P<0.05) between all diets (0.036/h in D4 to 0.081/h in D1). True digestibility was higher (P<0.05) in D4 (44.64%) compared to D1 (19.55%), but in D2 (24.54%) and D3 (28.22%) there was no difference. Cellulose in situ digestion rate, the potentially digestible fiber, was higher (P<0.05) in D3 (42.74%) as compared to D1 (22.50%). Time of disappearance of cellulose in D4 (14.79h) was less (P<0.05) than in D1 (24.03h), however there was no difference between D1 and D2. Hemicellulose in situ digestion was different (P<0.05) between D3 (45.48%) and D1 (23.61%). Digestion rate was higher (P<0.05) between D3 and D4 as compared to D1. Passage rate was different (P<0.05) between D4 (0.033/h) and D1 (0.018/h). True digestibility in D3 (34.84%) and D4 (34.62%) was higher (P<0.05) than that in D1 (20.06%) and D2 (25.86%). Half-time disappearance (t(1/2)) for hemicellulose was higher (P<0.05) in D1 (62.36h) than in D3 (28.00h) and D4 (20.64h). This study demonstrated that low quality forages at 70% of the total diet can be efficiently utilized by sheep when controlled-release urea supplementation is 30% of the feeding regime.

Effect of a controlled-release urea supplement on rumen fermentation in sheep fed a diet of sugar cane tops (Saccharum officinarum), corn stubble (Zea mays) and King grass (Pennisetum purpureum).

Four cannulated sheep were used to study ruminal fermentation of a diet consisting of 60% sugar cane tops (Saccharum officinarum), 30% corn stubble (Zea mays), 10% King grass (Pennisetum purpureum) and 0% (control), 10, 20 or 30% controlled-release urea supplement (CRUS) (diets 1, 2, 3 and 4, respectively). Average ruminal pH did not differ among diets (P>0.05), but during the first 6h of sampling tended to be higher for CRUS diets. Ammonia concentrations were higher (P<0.01) in all treatments over controls, indicating microbial protein generation. Acetic acid production (mM/1) decreased (P<0.05), propionic acid increased (P<0.05), while butyric acid production did not differ among CRUS diets and controls (P>0.05). Total amounts of ruminal VFA were lowest (P<0.01) in controls, while CRUS diets produced more of these energy sources. Supplementation of the high fiber diets with 10, 20 or 30% CRUS increasingly improved rumen fermentation, ammonia supply and VFA production. The results show that low quality forages (up to 70% DMI) can be used efficiently by sheep when conditions for ruminal microorganism are improved with a controlled-release urea supplement.

[Chemical composition and content of antiphysiological factors of jojoba (Simmondsia chinensis) residual meal]. / Estudio sobre la composición química y contenido de factores antifisiológicos de la pasta residual de jojoba (Simmondsia chinensis).

Jojoba (Simmondsia chinensis) is a perennial plant with an interesting economic value by processing it for liquid wax production. By pressing of jojoba seeds, by-product which has been called "residual meal" has been obtained, and because of its high protein content, it would be a great interest to evaluate it as animal feedstuff. The results of this study showed the following. Both seed and residual meal were analyzed in regard to their chemical proximal composition: crude protein 14.03 and 25.24%; ether extract, 48.89 and 14.73%; crude fiber, 10.03 and 10.07%; ash, 1.59 and 4.72, and nitrogen-free extract, 25.46 and 45.25, the limiting amino acids being methionine, lysine and isoleucine. The trypsin inhibitor factors were 13.747 and 11,197 TIU/g; and hemagglutinins and saponins were negative for both samples. Cyanogenic glucosides were positive in both samples. It was concluded that jojoba residual meal is an alternative as an adequate feedstuff in those regions where jojoba is produced. Nevertheless, prior to consumption it must be treated so as to eliminate the toxic factors.

Estudio sobre la composición quimica y contenido de factores antifisiologicos de la pasta residual de jojoba (Simmondsia chinensis) / Chemical composition and content of antiplysiological factors of jojoba (Simmondsia chinensis) residual meal

La jojoba (Simmondsia chinensis) es una planta que últimamente ha despertado grand interés mundial debido a la cera líquida que de ella se obtiene. Aun cuando se ha prestado mucha atención al uso potencial de esta cera como sustituto del aceite de ballena (cachalote), poco ha sido el trabajo efectuado sobre el subproducto, de elevado contenido proteínico, que queda después de la extracción del aceite. Considerando que una de las principales preocupaciones actuales es la búsqueda de nuevas fuentes de alimentos, tanto para consumo humano como animal, es clara la necesidad de efectuar un estudio sobre este producto. Como resultados significativos de la caracterización realizada se obtuvo: proteína cruda, 14.03 y 25.25%; extracto etéreo, 48.89 y 14.73%; fibra cruda, 10.03 y 10.07%; cenizas, 1.59 y 4.72, y extracto libre de nitrógeno, 25.46 y 45.25, siendo los aminoácidos limitantes la metionina, lisina e isoleucina; el inhibidor de tripsina, 13,747 y 11,197 UIT/g, y presencia de glucósidos cianogénicos en la semilla y la pasta, respectivamente. Se puede considerar, que por su valor nutritivo, la pasta residual de jojoba es un suplemento adecuado para la alimentación animal. Sin embargo, requiere de un tratamiento previo a su consumo para eliminar los factores tóxicos