SWINE RESEARCH REPORT 41

Transcription

1 AJINOMOTO ANIMAL NUTRITION AJINOMOTO HEARTLAND, INC. SWINE RESEARCH REPORT 41 Low CP Diets Formulated on a NE Basis Support Equivalent Performance of Growing-Finishing Pigs Introduction The increasing availability and declining cost of synthetic amino acids are opening opportunities for their increased use in commercial pork production. In addition to addressing environmental concerns relative to nitrogen excretion, research has proven that well formulated low protein diets can support pig performance equal to conventional diets. Objective To determine if low-protein diets with high levels of synthetic amino acids can support maximum performance of growing-finishing pigs. Experimental Design Six hundred and sixty growing pigs (330 castrates and 330 females) were separated by gender and housed in fully slatted concrete floor pens (5.8 x 2.4 m) in groups of 22 pigs per pen. Five pens were randomly allocated to each the three experimental diets to give 110 pigs per treatment. Experimental diets were based on wheat, barley and soybean meal and consisted of high (control), medium and low crude protein diets that were formulated to be nutritionally adequate in all nutrients. Synthetic L-Lysine HCl, DL-Methionine, and L-Threonine were used to meet the pig s requirements for these three essential amino acids in the diets. The diets (specified in Tables 1-3), as well as the diet costs (December 3, 2002 Western Canada) were balanced with respect to dietary electrolyte balance (deb) to ensure that this component did not confound results. As dietary protein level declines, the associated decline in potassium from soybean and increase in chloride from L-Lysine HCl, will cause a reduction in deb, which itself has been shown to impair animal performance. Maintaining minimum levels of deb across diets avoided this possible confounding effect. The apparent digestible lysine content was expressed on the basis of a ratio to net energy. The grow-out period was divided into three phases: 35 to 60 kg (Phase 1), 60 to 90 kg (Phase 2), and 90 to 115 kg (Phase 3). Both barrows and gilts received a common diet in Phase 1, but separate diets were used in Phases 2 and 3. Diets formulated with reduced protein but similar amino acid content were either similar in dietary cost or had reduced costs per tonne. Assuming equivalent biological performance and carcass composition, a reduction in dietary costs of an average of C4.00 per tonne represents an approximate feed cost saving of C1.00 per pig marketed. During each phase, pen weights and feed weighbacks were recorded; at the start, two weeks later, and when the target average weight was reached. Pigs were also weighed individually at the start of the experiment and at the first weighing after 90 kg to determine body weight variability. Carcass data were collected separately for each pig. Results Excellent performance was observed regardless of dietary crude protein level, with an overall ADG of 959 g per day and a feed efficiency of There were no significant effects (P>0.10) of dietary crude protein level on ADG, ADFI, FCR, or lean percentage (Figures 1-4).

2 Figure 1. ADFI SEM=0.025 Figure 3. Feed Efficiency SEM= kg/d Gain:feed Figure 2. ADG SEM=0.008 Figure 4. Lean Yield SEM= kg/d Lean yield, %

3 Discussion Results of this experiment suggest significant economic benefits of using low protein diets supplemented with synthetic amino acids for commercial pork production. Such diets are already recognized as an effective strategy for sustainable pork production, as well as beneficial for environmental preservation, as a result of reduced nitrogen excretion in the manure of pigs fed low protein diets. Low protein diets have also been shown to lower green house gas emissions. Using January 2003 prices, potential savings to producers as a result of a reduction in dietary protein and supplementation with synthetic amino acids are in the range of C4.00 per tonne equivalent to a feed cost saving of approximately C1.00 per pig. Increasing loin muscle thickness could potentially result in additional C2.00 per pig and up to C4.00 per pig depending on the loin premiums offered. When low protein diets are formulated on the basis of net energy, and dietary electrolyte balance is maintained, pigs can perform equally as compared to conventional diets. The feeding of high levels of synthetic amino acids (> 3 kg L-Lys/tonne) should not discourage nutritionists from formulating and recommending low protein diets. References Patience, J.F., A.D. Beaulieu, R.T. Zijlstra, D.A. Gillis, and J.L. Usry, The performance of grower-finisher pigs fed diets formulated to meet amino acid requirements but with declining crude protein content. Monograph 02-03, Prairie Swine Centre, Inc., Saskatoon, Canada 15 pp. Figure 5. Loin Muscle Thickness SEM= mm

4 Table 1. Composition of the experimental diets ( 35-60) kg TREATMENT Ingredients Wheat Soybean meal HP Barley Canola Oil Dicalcium Phosphate Limestone PSC Vitamin premix PSC Mineral premix Salt Sodium Bicarbonate L-Lysine HCL L-Threonine DL-Methionine TOTAL Cost/tonne ($) Nutrients N.E., Mcal/kg D.E., Mcal/kg Crude protein, % tlysine, % dlysine, % tmethonine, % dmethonine, % ttsaa, % dtsaa, % tthreonine, % dthreonine, % ttryptophan, % dtryptophan, % Calcium, % tphosphorus, % aphosphorus, % Sodium, % Chloride, % Potassium, % deb, meq/kg Analyzed diets Lysine Methionine Met+Cys Threonine Tryptophan

5 Table 2. Composition of the experimental diets (60 90 kg) TREATMENT Ingredients Wheat Soybean meal HP Barley Canola Oil Dicalcium Phosphate Limestone PSC Vitamin premix PSC Mineral premix Salt Sodium Bicarbonate L-Lysine HCL L-Threonine DL-Methionine TOTAL Cost/tonne ($) Nutrients N.E., Mcal/kg D.E., Mcal/kg Crude protein, % tlysine, % dlysine, % tmethonine, % dmethonine, % ttsaa, % dtsaa, % tthreonine, % dthreonine, % ttryptophan, % dtryptophan, % Calcium, % tphosphorus, % aphosphorus, % Sodium, % Chloride, % Potassium, % deb, meq/kg Analyzed diets Lysine Methionine Met+Cys Threonine Tryptophan

6 Table 3. Composition of the experimental diets ( kg) TREATMENT Ingredients Wheat Soybean meal HP Barley Canola Oil Dicalcium Phosphate Limestone PSC Vitamin premix PSC Mineral premix Salt Sodium Bicarbonate L-Lysine HCL L-Threonine DL-Methionine TOTAL Cost/tonne ($) Nutrients N.E., Mcal/kg D.E., Mcal/kg Crude protein, % tlysine, % dlysine, % tmethonine, % dmethonine, % ttsaa, % dtsaa, % tthreonine, % dthreonine, % ttryptophan, % dtryptophan, % Calcium, % tphosphorus, % aphosphorus, % Sodium, % Chloride, % Potassium, % deb, meq/kg Analyzed diets Lysine Methionine Met+Cys Threonine Tryptophan W. Bryn Mawr, Suite 650 Chicago, IL Tel: (773)