Effect of soybean variety and processing on growth performance of young pigs

Transcription

1 Effect of soybean variety and processing on growth performance of young pigs Maria Palacios, Robert A. Easter, Theodore Hymowitz 2, Kevin T. Soltwedel and James E. Pettigrew Department of Animal Sciences; 2 Department of Crop Sciences University of Illinois at Urbana Champaign Background The soybean is known as an excellent source of protein when formulating diets for swine. However, this potential can be achieved only if certain quantity of heat is applied. Osborne and Mendel (9) were the first to report that raw soybeans had a growth-depressing effect in rats. Generally, these heat labile factors are protease inhibitors, lectins, goigotrens and antivitamins. The most common way of eliminating these factors is by heating or toasting the soybeans in a processing plant, being sure that temperature, duration of the heating, particle size and moisture are controlled. Another way to inactivate these factors is by dry extrusion (without steam). It is well known that antinutritional factors present in raw soybeans can cause inhibition in growth, decreased feed efficiency, goiterogenic responses, pancreatic hypertrophy, hypoglycemia and liver damage in non ruminants animals depending upon species, age, size, sex, state of health and plane of nutrition. Liener (2000) defines protease inhibitors of soybeans as proteins that can be categorized as those that have a molecular weight of about 20,000 daltons and a specificity directed primarily against trypsin, known as the Kunitz trypsin inhibitor (Kunitz, 945); and those that have a molecular weight between,000 to 0,000 daltons and are capable of inhibiting chymotrypsin as well as trypsin at independent binding sites, referred as the Bowman-Birk trypsin inhibitor (Bowman, 944; Birk 9). Lectins are glycoproteins that have the ability to bind to carbohydrate containing molecules on the epithelial cells of the intestinal mucosa, in which the extent of this binding determines its toxicity. They are also called hemaglutinnins, based on their ability to agglutinate red blood cells (van Heugten, 200). Schulze et al. (995) conducted a study to investigate the metabolic flow of purified soy lectin incorporated in diets and their effect on nitrogen passing the terminal ileum. Isotopic nitrogen analysis of the ileal digesta collected in this manner revealed an increased loss of endogenous nitrogen, which was attributed to increased secretion of protein, resulted from damaged caused by lectin on the intestinal mucosa. Performance of pigs fed raw Kunitz free soybeans is adversely affected, in the nursery and the grower stages. Growth reductions of 44% and 8% were observed in pigs fed raw Kunitz free soybeans, compared to a soybean meal diet (Stickler, 992). This research suggested that raw soybeans free of the Kunitz trypsin inhibitor still have others antinutritional factors that affect growth in pigs. Douglas et al. (999), conducting a study in male chicks from 8

2 to days of age, suggested that the nutritional value of raw lectin free soybeans is greater than raw conventional soybeans but is less than raw Kunitz free soybeans and soybean meal, suggesting that the trypsin inhibitor is a greater antinutritional factor than lectins. The objective of this study was to evaluate the efficacy by which two different genetically modified soybeans improve growth performance in young pigs. The varieties tested were: Williams 82 (WM), a commercial variety; Isoline L90-804, a lectin free variety (LF) and Isoline X9-00, a lectin free and Kunitz trypsin inhibitor free variety (LFKF). Materials and Methods One hundred and forty gilts and barrows with an average initial weight of.89 kg were randomly assigned to one of the following dietary treatments for a period of 28 days. Each variety of soybean was fed as raw (R) or as dry extruded (E) soybeans in a corn soybean diet. Commercially available heated, solvent-extracted dehulled soybean meal (SBM) was included in a corn soybean meal diet as the positive control. A total of seven dietary treatments formulated to.0% lysine and 00 kcal DE/kg were used in this study (Table ):.SBM, 2.WM E,.LF E, 4.LFKF E, 5.WM R,. and.. Pigs were housed in a mechanically ventilated grower facility at the University of Illinois Swine Research Center in partially slatted floors. Feed and water were available ad libitum. Individual pig weights and pen feed intakes were recorded weekly. The study was conducted as a Randomized Complete Design with treatments, 5 blocks/treatment and 4 pigs / pen (2 gilts and 2 barrows). Results and Discussion The overall daily weight gain (kg/pig), overall daily feed intake (kg/pig) and overall gain: feed ratio (g: kg) are presented in Table 2, Table and Table 4 respectively. Performance was similar (P>0.05) among pigs fed the SBM and the extruded soybean diets but was poorer (P<0.05) in pigs fed raw soybean diet. The percentage of growth-rate depression and restoration in growth as a result of comparing average daily gain (ADG) among treatments is presented in Table 5. The percentage of performance is obtained by dividing the ADG using a raw soybean by the ADG using an extruded soybean, within the same variety. The percentage of depression is obtained by subtracting the percentage of performance from 00%. From the results of this trial, the performance in ADG increases as we reduce the amount of antinutritional factors in raw soybeans. Therefore the WM variety, that contains both Kunitz trypsin inhibitor and lectins, produces more depression in growth than a lectin-free variety of soybean (LF variety). Furthermore, a lectin-free Kunitz-free variety of soybean (LFKF variety) produces the least depression when compared to WM and LF varieties. Conclusion The depression in growth performance of young pigs fed a raw commercial variety was partially restored to the extent of 22% by using a lectin free variety (Isoline L90-804) and to the extent of 55% by using a lectin-free Kunitz free variety of soybean (Isoline X9-00), relative to the Williams 82 variety (commercial variety). Therefore, when using raw genetically modified varieties of soybeans for feeding young pigs, there is still a 45% of

3 depression originated by other heat labile factors different than lectins and the Kunitz trypsin inhibitor. References Birk, Y. 9. Purification and some properties of a highly active inhibitor of trypsin and chymotrypsin from soybeans. Biochem. Biophys. Acta 54:8-8. Bowman, D.E Fraction derived from soybean and navy beans which retard tryptic digestion of casein. Proc. Soc. Exp. Biol. Med. 5:9-40. Douglas M.W., Parsons C.M., Hymowitz T Nutritional evaluation of lectin free soybeans for poultry. Poult. Sci. Jan; 8():9-95. Drackley, J.K Soy in Animal Nutrition. In: Liener, I.E. Non-nutritive factors and bioactive compounds in soy. p -45. Federation of Animal Science Societies. Savoy, IL. Kunitz, M Crystallization of a trypsin inhibitor from soybeans. Science 0:8-9. Lewis, A.J. and L.L. Southern Swine Nutrition. In: van Heugten, E. Mycotoxins and other antinutritional factors in swine feeds. p nd edition. CRC Press. Washington, D.C. Osborne, T.B. and L.B. Mendel. 9. The use of soybeans as food. J. Biol. Chem. 2:9-8. Schulze, H., H.S. Saini, J. Huisman, M. Hessing, W. van der Berg, and M.W.A. Verstegen Increased nitrogen secretion by inclusion of soya lectin in the diets of pigs. J. Sci. Food Agric. 9: Stickler, M.T Effect of feeding the Kunitz trypsin inhibitor free soybean on swine growth performance. Master Thesis in Animal Science. University of Illinois. Urbana- Champaign.

4 Table. Composition (%) of the experimental diets (as-fed basis). Ingredient 2, 5, 4, Corn Soybean meal Soybean Soybean oil Dicalcium phosphate Limestone Trace mineral premix Vitamin premix Soybean included as dry extruded for diets 2, and 4 or included as raw (ground) for diets 5, and. 2 Provides per kg of diet: Fe, 49. mg (FeSO 4 H 2 O); Zn 5. mg (ZnO); Mn,. mg (MnO); Cu. mg (CuSO 4 H 2 O); I, 0. mg (CaI 2 ); Se, 0.5 mg (Na 2 SeO ); NaCl 4. g. Provides per kg of diet: retinyl acetate, 2,2 µg; cholecalciferol, µg; dl-α-tocopherol acetate, 88 mg; menadione sodium bisulfite complex, 4 mg; niacin, mg; d-capantothenate, 24 mg; riboflavin; 9 mg; vitamin B 2, 5 µg; choline chloride, 24 mg. Table 2. Overall daily weight gain (kg/pig). SBM 2 WM E LF E Treatment Mean a a 0.4 a 0.40 a 0.0 c 0.4 b,c 0.2 b a,b,c,d Values within a row with uncommon superscripts may differ (P<0.05) Table. Overall daily feed intake (kg/pig). SBM 2 WM E LF E Treatment Mean 0.8 a a 0.29 b 0.5 a,b 0.52 d c 0.08 b a,b,c,d Values within a row with uncommon superscripts differ (P<0.05)

5 Table 4. Overall gain:feed ratio (g:kg) 2 SBM WM E LF E Treatment Mean 424 a 499 a 540 a 4 a c 2 b,c 9 a,b a,b,c Values within a row with uncommon superscripts differ (P<0.05) Table 5. Comparison among treatments, ADG (kg/pig/day) ADG Dietary treatment WM LF LFKF Raw 0.0 c 0.4 b,c 0.2 b Extruded a 0.4 a 0.40 a % Performance 22% 9% 5% %Depression 2 8% % 5% Standardizing WM % Depression = 00% 00% 8% 45% % Restoration 0% 22% 55% a,b,c Values with uncommon superscripts differ (P<0.05) %Performance = (ADG (Raw) / ADG (Extruded))*00 2 % Depression = 00 - % Performance % Restoration = 00% - Standard value