Abstract 331

Lindemann,-MD; Kornegay,-ET; Moore,-RJ

Dep. Animal Science, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061, USA.

Journal-of-Animal-Science. 1986, 62: 2, 412-421; 27 ref.

Twenty-four crossbred gilts weighing 72 ñ 0.7 kg were used in 2 balance trials to estimate the digestibility of nutrient components of groundnut husks. Groundnut husks had nitrogen 1.44, neutral detergent fibre 63.6, acid detergent fibre 56.3, cellulose 45.5, hemicellulose 7.5 and lignin 7.7%. They contained calcium 0.09, phosphorus 0.09, magnesium 0.09 and potassium 0.25% with iron 295, sodium 48, manganese 34, zinc 24 and copper 14 mg/kg. Gross energy was 4380 kcal/kg. As husks were substituted for the basal diet (7.5, 15 or 30%) digestion coefficients for DM, N, energy, neutral detergent fibre, lignin, hemicellulose and ash were decreased (P<0.001). Net retention of Ca, P, Na, Mn and Zn was reduced (P<0.02) with increasing amount of husks. Reductions in Na, Mn and Zn retentions were evident only when husks exceeded 7.5% of the diet. The estimated digestibilities of the components of husks, calculated by regression utilizing the percentage of each component in the total diet supplied by husks, were: DM 28.8, N 29.6, energy 32.5, neutral detergent fibre 14.9, acid detergent fibre 16.4, lignin 19.8, cellulose 19.5 and hemicellulose 0.0%. Two feeding trials, utilizing 120 crossbred pigs, were made to evaluate the effects of husks on growth performance. Husks were added at 0, 7.5, 15.0 and 22.5% to a 14.8% crude protein maize-soyabean oilmeal growing diet (29 to 60 kg) and a 13.8% crude protein finishing diet (60 to 99 kg). There was no difference (P>0.05) in daily gain during either period of the trials caused by husks in the diet. The maintenance of similar gains was accomplished by linear increases in daily feed intake during the growing (P<0.05) and finishing period (P<0.001).