Nutrient Intake, Digestibility and Nitrogen Balance in Yankasa Rams fed Treated Ensiled Eggplant (Solanum melongena) or Digitaria smutsii hay

Abstract

Forty  Yankasa breed of weaner rams weighing 9.15+3.11 W_kg^0.75 were used for digestibility trial to evaluate the nutritive value of treated ensiled eggplant (Solanum melongena) forage. Wilted, chopped eggplant forage was sprayed with 0.4% solution of urea, saline, equal proportion of urea-plus-saline, or water in a ratio of 1:4 (v: w) solution to forage. The treated forage was ensiled air-tight in black polythene bags for 21 days. Each of the treated forage constituted a treatment to which 8 animals were assigned in a randomized complete block design after balancing for weight. Digitaria smutsii hay was fed as control roughage in the 5^th treatment. The assigned forage or hay was fed at 3% of body weight and supplemented with concentrate at 2% of body weight. The digestibility trial lasted 14 days for animals to adjust to the feed and crates, and 7 days for fecal and urine collection for laboratory chemical analysis to determine DM, CP, CF, EE, ash, NDF and ADF. Organic matter and NFE were derived from the results of the chemical analysis. Data collected for feed intakes, fecal and urine outputs, nutrient digestibility and nitrogen balance were analyzed by ANOVA using GLM procedure of SAS package, and means compared by Duncan Multiple Range Test. Crude protein in the urea-treated forage (30.13%) was more than 5 times that of the least (5.44%) in D. smutsii hay. Forage and total DM intakes (62.92 and 108.45g/ W_kg^0.75 respectively) were highest (P<0.05) and the correspondent values for the hay (55.25 and 99.65g/ W_kg^0.75 respectively) were least. Forage crude protein intakes for the treated forage ranged from 15.22 to 17.64 g/W_kg^0.75 and was higher (P<0.05) than for the hay (3.05 g/W_kg^0.75). The forage and total NFE intakes from the hay ((28.61 and 50.04g/W_kg^0.75 respectively) were higher (P<0.05) than the least (14.24 and 35.34 g/W_kg^0.75 respectively) in the saline-treated forage. The water-treated forage had the highest (P<0.05) digestibility for DM and OM (68.17 and 72.12% respectively). The highest (P<0.05) CP digestibility (81.01%) was for urea-treated forage and the least for the hay (64.55%). Nitrogen-free extract digestibility was highest (P<0.05) for the hay (95.83%) and least for the saline-treated (91.67%). Nitrogen intakes of the treated forage ranged from 4.23 to 4.60 g/W_kg^0.75 but significantly (P<0.01) differed from the intake in Digitaria hay (2.23 g/W_kg^0.75).  Highest (P<0.01) nitrogen retention was for urea-treated (2.99 g/W_kg^0.75) and least for the hay (1.13 g/W_kg^0.75). Urea-treated forage had the highest (P<0.01) per cent nitrogen retention (63.59%) and saline-treated forage the least (44.95%). Ensiling eggplant (Solanum melongena) forage treated with 0.4% of urea, saline, equal proportion of urea-plus-saline, or water for 21 days transformed the forage from a farm waste to consumable forage with better nutrient intakes, digestibility and nitrogen retention in sheep than Digitaria smutsii hay.

Keywords: Eggplant nutrient intake and digestibility; nitrogen retention; Yankasa weaner rams