Effects of Dietary Protein Content and Crystalline Amino Acid Supplementation Patterns on Growth Performance of Weaned Pigs Raised Under Different Sanitary Conditions
Published:March 11, 2021
By:J. Caroline González-Vega – Evonik Operations GmbH. John K. Htoo, n/a – Evonik Operations GmbH. Jinyoung Lee, MSc, University of Manitoba. Chengbo Yang, Associate Professor, University of Manitoba. Martin Nyachoti, Professor and Head, University of Manitoba.
The objective of this experiment was to determine the effects of dietary crude protein (CP) content and crystalline amino acids (CAA) supplementation patterns on the growth performance of weaned pigs under clean (CSC) or unclean sanitary conditions (USC). One hundred forty-four piglets (6.35 ± 0.63 kg BW) were housed under CSC or USC for 3 wk and assigned to 1 of 3 diets: a high CP (HCP; 21%) and two low CP (LCP; 18%) diets supplemented with 10 crystalline indispensable amino acids (IAA) to meet all IAA requirements or only 6 IAA (Lys, Met, Thr, Trp, Val, and Ile) to meet IAA requirements except Leu, His, and Phe. Each treatment had 8 replicates (3 pigs per pen) per sanitary condition. The CSC room was cleaned and washed weekly. For the USC room, sow manure was spread and remained unwashed. Data were analyzed using the MIXED procedure of SAS with orthogonal polynomial contrasts. Pigs raised under USC had reduced (P < 0.05) ADG and G:F in wk 2, but overall, no difference was found between sanitary conditions due to contrary results in wk 3. Overall, ADG and ADFI were not affected but G:F tended (P < 0.10) to be lower for USC pigs. Also, G:F did not differ between HCP (0.79) and LCP (0.81) under CSC, however, LCP interactively decreased (P < 0.05) G:F to 0.75 compared to 0.83 in HCP under USC. The CAA supplementation patterns did not influence growth except reduced (P < 0.05) ADFI in wk 3. Pigs fed the HCP diet had higher (P < 0.05) fecal scores throughout the experiment than those fed LCP diets under both sanitary conditions. In conclusion, overall growth performance did not differ between HCP and LCP under CSC, but LCP diets reduced G:F under USC. The fecal score decreased in LCP diets regardless of sanitary conditions.
Dr. Nyachoti, as the possible basis for the results obtained was lacking, with the presentation of only the summary, there were some doubts that I believe are important. Taking advantage of his vast experience in the subject, he would like to make the following considerations. FIRST; I believe that, in the case of a study involving different sanitary conditions, it would be interesting to evaluate some parameters of the animals' immune system, in order to characterize the efficiency of the challenge methodology used. SECOND; as food consumption did not vary between treatments, the best feeding efficiency of animals in an unchallenged environment should not improve their weight gain. In this specific case, even if this possible improvement is not significant, it could not be presented as a percentage of increase.
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