Impact of reduced dietary crude protein concentration with crystalline amino acid supplementation on lactation performance and ammonia emission of sows housed under thermo neutral and thermal heat stress environments

Abstract Text:

The objective of this study was to test the hypothesis that feeding a diet containing lower dietary CP and supplemental crystalline AA compared to a diet meeting Lys requirement without supplemental AA, reduces ammonia emission, and maintains lactation performance in sows housed under thermo-neutral and thermal heat stress environments. Thirty-six, multiparus, sows were allocated to a 2 × 2 factorial arrangement of 2 temperatures, thermo-neutral (21°C; TN) and heat stress (31.5°C; HS), and 2 diets, 17.16 (Control) and 11.82% CP (Low), in a randomized complete block design. The HS sows were acclimated during late gestation to increasing temperature from 21 to 31.5 °C. During lactation, temperature for HS sows were incrementally changed (24 to 31.5°C and 31.5 to 24°C) from 0500 to 1500 and 1800 to 0500, respectively. Control diet met SID Lys requirement with no added CAA and Low diet contained added crystalline Lys, Thr, Trp, Val and Phe. Compared to Control, piglet ADG, sow feed intake (FI), true milk protein (TMP), weight loss (DBW), heart rate (HR), and respiration rate (RR) of Low sows did not differ. Compared to Control, MUN and ammonia emissions decreased for sows fed Low (P < 0.0001). Change in back fat (DBF), body temp (BT), and days post weaning to estrus (WtE) did not differ between diets. Compared to TN, DBW, HR and RR of HS sows were greater (P < 0.05). Compared to TN, piglet ADG of HS sows were less (P <0.05).  In conclusion, feeding reduced CP diet to lactating sows improved N utilization and did not impact lactation performance of sows under either thermo-neutral or thermal heat stress environments.  These results indicate that reduction of dietary CP in conjunction with aggressive CAA supplementation may be implemented for lactating sows to mitigate ammonia emissions while maintaining lactation performance.

Item   Thermoneutral Heat Stress SEM   Diet Environment Control Low Control Low P-value P-value Sow FI, kg/d 5.20 5.56 4.28 4.28 0.26 0.299 0.011 Sow DBW, kg/d -0.30 -0.63 -0.84 -0.84 0.19 0.368 0.044 Piglet ADG, g/d 263.3 279.2 236.7 235.2 9.70 0.426 0.001 Sow DBF, mm -1.46 -2.74 -3.22 -2.17 1.01 0.680 0.445 WtE, d 7.68 7.22 7.00 5.67 1.13 0.777 0.971 HR, beats/min 69.38 69.87 89.98 91.00 7.23 0.960 0.042 RR, breaths/min 71.74 69.37 93.81 93.27 6.37 0.951 0.014 BT, °C 36.83 37.66 37.77 38.02 0.86 0.830 0.420 MUN, mg/dL 9.46 2.35 9.83 1.92 0.72 <.0001 0.979 TMP, % 4.47 4.29 4.64 4.55 4.30 0.184 0.028 Ammonia, g/d 34.2 11.2 26.8 12.9 2.9 <.0001 0.351

Keywords:

Sow, Amino Acid, Ammonia Emission