305 Does heat stress alter the pig's response to dietary fat source, as it relates to apparent or true total tract digestibility of dietary lipids?. (1st April 2016)

• Record Type: Journal Article
• Authors: Kellner, T.; Baumgard, L. H.; Patience, J. F.
• Is Part Of: Journal of animal science. Volume 94(2016)Supplement 2
• Page Start: 143
• Page End: 143
• Publication Date: 2016-04-01
• Subjects: heat stress -- fat digestibility -- and energy intake; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.2527/msasas2016-305
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: The objective was to investigate the effect of heat stress on the pig's response to dietary fat in terms of growth performance and digestibility of apparent (ATTD) and true total tract digestibility (TTTD) of acid hydrolyzed ether extract (AEE) over a 35 d finishing period. A total of 96 barrows (PIC 337 × C22/29) with an initial BW of 100.4 ± 1.2 kg were randomly allotted to 1 of 9 treatments arranged as a 3 × 3 factorial: [TN (thermonetural: constant 24°C; ad libitum access to feed), PFTN (pair-fed thermoneutral: constant 24°C; limit-fed based on previous HS daily feed intake), or HS (heat stress: cyclical 28°C nighttime, 33–35°C daytime; ab libitum access to feed)] and diet [a corn-soybean meal based diet with 0% added fat (CNTR), 3% added tallow (3%TAL; iodine value = 41.8), or 3% added corn oil (3%CO; iodine value = 123.0)]. Pigs were individually housed (1.25 m 2 /pig). Titanium dioxide was included as an indigestible marker at 0.4%. Fecal samples were collected on d 17 (∼ 114 kg BW). TTTD (%) of AEE was calculated via correcting ATTD of AEE for endogenous fat losses at 20 g of AEE/kg of dry matter intake. Data were analyzed using PROC MIXED with environment and dietary treatment as fixed effects, and replicate (2 replicates of 48 barrows) as a random effect. Rectal temperature increased due to HS (HS = 39.0, T N = 38.1, PFT N = 38.2°C; P < 0.001). HS decreased ADFI (27.8%; P < 0.001), ADG (HS = 0.72, T N = 1.03, PFT N = 0.78 kg/d; P < 0.001), and G:F (HS = 0.290, T N = 0.301, PFT N = 0.319; P = 0.006). G:F but not ADG or ADFI tended to be influenced by dietary treatment (CNTR = 0.292, 3%TAL = 0.303, 3%CO = 0.314 g/100 g; P ≤ 0.073). HS tended to result in the lowest ATTD of AEE (HS = 59.0, T N = 60.2, PFT N = 61.4%, P = 0.055). Inclusion of dietary fat, and a source that was unsaturated increased ATTD of AEE (CNTR = 41.6, 3%TAL = 67.9, 3%CO = 71.2%, P < 0.001). TTTD of AEE of 3%CO-based diets (99.3%) was higher than that of CNTR (97.3%) and 3%TAL-based diets (96.3%; P = 0.012). Environment had no impact on TTTD of AEE ( P = 0.118). In summary, ATTD, but not TTTD of AEE was decreased by HS exposure.