title: Effect of source of supplemental nitrogen on the utilization of citrus pulp-based diets by sheep.
abstract: Two trials were conducted to examine the influence of N enrichment of dried citrus pulp (DCP) through ammoniation vs urea supplementation on digestion and feeding value of a DCP-based diet for sheep. Treatments were 1) ammoniation of DCP with urea (CP-U), 2) ammoniation with ammonium hydroxide (CP-A), 3) supplementation with urea, and 4) supplementation with horse bean (HB). Diets were isonitrogenous (1.8% N). In Trial 1, treatment effects on characteristics of digestion were evaluated in a 4 x 4 Latin square experiment using four rams. Source of supplemental nonprotein N (NPN) did not influence (P > .10) ruminal OM digestion. Net microbial N synthesis, N absorption, N retention, and microbial efficiency were greater (P < .05) for the CP-U than for the CP-A or urea diets. Apparent N digestibility of CP-A was 14 to 25% lower (P < .05) than that of the other diets supplemented with NPN. In Trial 2, treatment effects on lamb growth performance were evaluated in a 105-d growing-finishing trial involving 32 Sardi lambs (19 kg). Intake was similar (P > .10) across treatments (1.13 kg of DM/d). Daily gain of the urea-fed lambs (182 g) was higher (P < .05) than that of CP-U- or CP-A-fed lambs (138 g). Feed efficiency and dietary NE values were similar (P > .10) among diets containing NPN. Growth performance seemed to be more directly affected by intake, rather than N economy. Enrichment of DCP through ammoniation with urea was a superior method of NPN supplementation with respect to efficiency of N utilization. However, the ultimate response to the potential benefits of such treatment may be seen only if N is truly limiting performance.
authors.affiliation: Animal Science Department, Institut Agronomique et Veterinaire, Hassan II, Rabat Instituts, Morocco.
authors.forename: N
authors.initials: N
authors.lastname: Rihani
authors.forename: W N
authors.initials: WN
authors.lastname: Garrett
authors.forename: R A
authors.initials: RA
authors.lastname: Zinn
mesh_terms: D000641:Ammonia / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D002957:Citrus; D004043:Dietary Fiber; D004063:Digestion; D004435:Eating; D005232:Fatty Acids, Volatile / Q000032:analysis; D005527:Food, Fortified; D006863:Hydrogen-Ion Concentration; D008297:Male; D009584:Nitrogen / Q000008:administration & dosage* / Q000378:metabolism; D012417:Rumen / Q000737:chemistry / Q000502:physiology; D012756:Sheep / Q000254:growth & development / Q000502:physiology*; D014508:Urea; D015430:Weight Gain
chemical_list: D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D000641:Ammonia; D014508:Urea; D009584:Nitrogen