Lupins (Lupinus albus var. Ultra) replace a part of soybean meal in diets for growing chickens.

Abstract

LUPINS (Lupinus albus var.Ulta) REPLACE A PART OF SOYBEAN MEAL IN DIETS FOR GROWING CHICKENS Rafael Perez-Escamilla* and Pran Vohra* SUMMARY The gain %n body weight of broilers fed diets containing up to 30% sweet raw lupins or 35% autoclaved lupins was not significantly different from that of broilers fed a corn-soybean meal diet. Lupin hulls did not appear to be deleterious for broilers. INTRODUCTION The main source of plant protein in poultry diets is soybean meal and the main suppliers are the U.S.A., Brazil and Argentine. Animal nutritionists are interested in alternative sources of plant protein from legumes which may be cultivated under more diverse conditions. Lupins could fill that role. Lupins have been cultivated in some Mediterranean countries and in some highlands of the Americas as a minor legume for food since ancient times. The commonly grown species (Lupinus albus, L. an ustifolius, L. luteus in Mediterranian region and L. mutabimn Amerxas have a high crude protein (CP) content but may -r also contain alkaloids like lupanine and 13-hydroxyl upanine which impart a bittertaste.The alkaloid content may be 0.5 to 2% in bitter varieties (Gladstones, 1982). The alkaloids reduce the palatability of lupin-containing diets. The- alkaloid content can be reduced by soaking and boiling the seeds in water for a long time and discarding the water (Johnson et al,, 1986.). However, plant breeders have developed sweet lupins with alkaloid content as low as 0.01% (Ruiz, 1976; Gladstone, 1982). Satisfactory broiler growth was obtained by incorporating lupin meal from Uniwhite, a sweet variety of L. augustifolius in diets at levels of 15% (Smetana and Morris,1972).Adiet containing 24% lupin meal supported as good a growth of broilers as their wheat-safflower meal contpol diet (Yule and McBride, 1976). Bitter or sweet lupins were fed at levels of 40% in broiler diets and the broilers reached a body weight of 1.886 kg and 1.215 kg as compared to a weight of 2.046 kg on a corn-soybean diet (Guillaume et al., 1979). Erickson (1985) reported depressed daily gains in broilersby adding 10X, 20X, and 30% ground lupins to replace corn in their diets. Autoclaving of lupin (L. albus var. multulupa) for 30 minutes at 120' significantly improvedthe-thf broilers as compared to raw lupins. Lupins were used at levels of 6.4% and 12.8Xto replace 20% and 40% protein from soybeans in broiler diets (Molina et al., 1983). 169 Watkins et al. (1987) fed raw, autoclaved or extruded lupins (L. albus cv Ultra) in broiler diets and observed that growth and feed conversion of chicks fed more than 10% lupins were inferior to controls fed no lupins. However, chicks fed 10% extruded lupins were significantly heavier than the controls. The diet had to be supplemented with methionine and lysine. Galactan content is high in lupin hulls but it is doubtful that they act as toxicants for chickens (Carre and Leclercq, 1985). Halvorson et al .(1983) determined the true metabolizable energy (TME) of 1upinsTorturkeys as 2.64 kcal/g. A value of 2.2 kcal TME/g was found for adult male chickens (Watkins et al., 1987). Halvorson et al. (1983) observed no depression in growth of turkeys at 3 weeksofage when fed lupins (L.albus) at a level of 15% . -*in a diet supplemented with lysine and methlonlne. We have further studied lupins (L. albus var Ultra) for their usefulness in supporting the growth of chxkens. METHODS AND MATERIALS Lupins grown in California were supplied by Mr. T.E. Kearney of the Coop. Extension of the University of California, Davis. The seeds were dissected and the hulls were separated manually to obtain endosperm for analysis. The proximate analyses of the ground lupins was carried out acording to AOAC (1975). Acid detergent fiber (ADF), neutral detergent fiber (NDF), cellulose and lignin were determined by the procedure of Goering and Van Soest(1975). Coarsely ground lupins were autoclaved for 15 minutes-at 121OC. During grinding, lupins tend to plug up fine screens. Amino acid profiles of a sample were determined after acid hydrolysis by ion-exchange chromatography. Broiler (Hubbard) chicks (Experiments 1 and 2), and New Hampshire chicks (Experiment 3)~ were purchase from A and M Hatchery, Santa Rosa, CA They were banded, weighed and distributed into groups of apiroximately an equal weight. The birds were housed in electrically heated battery cages. Water and feed were available all the time. The conventional system of management for this age of chickens were. followed. The composition of the diets (or feeds) is given in Tables 4, 6, and 8. Each diet was fed to duplicate group of birds housed randomly in the battery. The individual body weights of birds and the 'group diet intakes were recorded two times each week. There is a waste of diet initially and this is the reason for not recording diet intakes from day one. The feed intake over the last 3 days of the Experiments 1 and 2 was measured, and the corresponding excreta were collected for AME determination. The birds were killed by cervical dislocation and liver and pancreas were co1 lected and weighed. The data on gain in body weight, feed intake/gain in body weight, and on liver or pancreas weights as % of body weight were subjected to analysis of variance to determine any significant differences. Least significant difference (LSD) values were calculated where applicable. 170 RESULTS AND DISCUSSION The proximate composition of lupins and the endosperm is given in Table 1. Table 1, Proximate composition of lupins The analysis of the carbohydrate 2. The endosperm has much lower levels which are mostly concentrated in the like galactans are solublized and lost Table 2. complex is given in Table of NDF, ADF and cellulose hulls. Pectic substances during NDF measurements. Carbohydrate and lignin content of lupins The amino acid profile (Table 3) indicates that lupin protein has a lower concentrati.on of the amino acids isoleucine, lysine, methionine, phenylal anine and valine than the soybean protein. Cystine and arginine are more abundant in lupins than in soybeans. However, cystine only spares methionine but doe not replace it. For this reason, diets containing lupins need to be supplemented with methionine and lysine. Table 3. Amino acid profile of lupins and soybeans (g/l6 g N) The diet in Experiment 1 was formulated to test the maximum incorporation of raw lupin meal in diets for broiler chicks. A value of 2.4 kcal AME/g for lupins was used as diets were formulated before AME has been determined. The composition of the diet is given in Table 4. 171 A corn-soybean meal diet served as control and the test diets contained 10X, 20%, 30% or 35% raw lupins. No broilers control A level weights. lupins. diets. significant difference (PcO.05) in gain in body weight of was observed over a 21 day period when they were fed either the diet or diets containing 10X, 20% or 30% raw lupins (Table 5). of 35% raw lupins significantly depressed the gain in body Feed efficiency was poorest if the diets contained 30% or 35% Raw lupins can be safely used up to a level of 30% in broiler Table 5. Gain in body weight and feed efficiency of broilers fed raw lupin diets in Experiment 1 The effect of autoclaving of lupins was studied in Experiment 2 using the diets of the composition given in Table 6. 172 Table 6. Composition of the control and lupin diets (Expt. 2) No significant difference was observed in or feed efficiency of broilers fed either raw or autoclaved lupins at levels of 201, Autoclaving of lupins appears to improve their the gain in body weight lupins at a level of 30% 30% or 35% (Table 7). nutritional value. Table 7. Gain in body weight of broiler chicks fed lupin diets and their feed eficiency Lupins contain a high level of galactans in the hulls which can be hydrolyzed with the enzyme hemicellulase. If galactans caused any growth depressi on, it should be overcome by suplementing the lupin diets with hemicellulase. This hypothesis was tested in Experiment 3 using diets of the composition given in Table 8. Both raw and autoclaved lupins were tested at a level of 65% in the diet. 173 A level of 1% hemicellulase did not significantly improve the gain in body weights of the birds fed the control diet (Table 9). A level of 65% raw or autoclaved lupins significantly reduced the gain in body weight of New Hampshire chickens which was not overcome by the addition of hemicellulase enzyme. This suggests that galactans in hulls do not have any growth depressing effect confirming the observtion of Carre and Leclercq (1985). 174 It may be concluded that raw lupins can be incorporated in broiler diets up to levels of 30% and after autoclaving, the level may be increased to 35%. Lupin hulls do not appear to be involved in growth dpression of chickens. Liver and pancreas weights were not significantly increased on various dietary treatments implying a lack of toxicants in sweet (low alkaloid) lupins. REFERENCES AOAC (1975). Official Methods of Analysis. Association of Official Analytical Chemists, Washington, DC. Carre, 8. and Leclercq, 8. (1985). Br. 3. Nutr. 54: 669. Erickson, J.P. (1985). Feedstuffs, 57 (q:r Gladstones,J.S.(1982).3. Agric. GsternAustralia,23: 70. Goering, H.K. and Van sest, P.J. (1975). U.S.D.A. Agric. Handbook No. 379 Guillaum'e, J . , Chenieux., J.C. and Rideau, M. (1979). Nutr. Reports Internat.20: 57. Johnson, Jr., Ji., Miller, J.D. and Bedell, D.M. (1986). 3. Dairy Sci. 69: 142. Molina, E., Sanz, R., Boza, 3, and Aguilera, 3. (1983). Arch. zootecnia, 32: 295. Ruiz,Tr., L.P. (1976). N.Z. 3. A ric. Res. 20: 51. Smetana, P. and MorrisxHT(197 . Proc.Aust. Poultry Sci. Conv., + Auckland, N.Z. p. 209. Watkins, B.A., Manning, 8. and Al-Athari, A.K. (1987). Poultry Sci. (in Press). Yule, W.J. and McBride, R.L. (1976). Br. Poultry Sci. 17: 231, P- 175