FIELD PEAS - CHEMICAL-COMPOSITION AND ENERGY AND AMINO-ACID AVAILABILITIES FOR POULTRY

Twelve pea cultivars (yellow-, green- and brown-seeded) were evaluated for chemical composition and digestibility in poultry. The evaluation involved analyses for protein, amino acids (AAs), fat, starch, dietar y fibre, ash, calcium, phosphorus and tannins. True metabolizable ener gy [nitrogen corrected (TMEn) and uncorrected (TME)] and true AA bioav ailability values were also determined with adult cockerels. The culti vars showed a wide range of protein (207.5-264.0 g kg(-1)) and starch (385.3-436.8 g kg(-1)) contents which were not related to the seed coa t colours. The concentrations of several AAs varied among the cultivar s. With the exception of arginine, the concentrations of all other ess ential AAs on a protein basis decreased as protein levels increased. O ut of 10 essential AAs including cystine, only arginine had a positive correlation (r = 0.79) with protein content. The dietary fibre conten ts varied between 190.7 and 223.1 g kg(-1) and the values were slightl y higher in the brown-seeded cultivars. The brown-seeded cultivars con tained appreciable quantities of tannins, while the yellow- and green- seeded cultivars were devoid of tannins. The cultivars were almost dev oid of fat and calcium but relatively high in phosphorus. Starch and d ietary fibre were negatively correlated with protein content (, = -0.7 8 and -0.46, respectively), and accounted for the greatest difference in protein content. The TME values ranged from 11.6 to 13.3 MJ kg(-1) while the TMEn values ranged from 11.0 to 12.9 MJ kg(-1). The mean ava ilabilities of AAs ranged from a high of 89.6 to a low of 75.9%, with total sulphur AAs (cystine and methionine) having the lowest value and glutamic acid having the highest value. There was a trend (P less tha n or equal to 0.05) towards lower AA bioavailability values in the bro wn-seeded cultivars. It can be concluded that these cultivars varied i n chemical composition, metabolizable energy content and bioavailabili ty of AAs.