| Summary: | Pigs exposed to elevated ambient temperatures exhibit reduced average daily gain, alterations in muscle and fat deposition during growth phases, and decreased overall health. Negative aspects of gastrointestinal (GI) function, integrity and permeability also result from hyperthermia. Saccharin-based artificial sweeteners have the potential to ameliorate the negative effects of heat stress (HS) by increasing GI GLP-2 production while capsicum oleoresin has been shown to reduce inflammatory response. Study objectives were to examine the effects of two artificial sweeteners, neohesperidin dihydrochalcone and saccharin, in combination with capsicum oleoresin (TakTik Sweet Heat , Pancosma, SA) on growth performance of pigs. Forty-eight pigs (12 weeks of age, 47.3 ± 7.6kg) were assigned to six treatments: thermal neutral conditions (21°C) fed ad libitum with (TN+) or without supplement (TN-), heat stress (35°C) fed ad libitum with (HS+) or without supplement (HS-), and thermal neutral conditions pair-fed to HS intake with (PFTN+) or without supplement (PFTN-). Dietary supplementation began 2 days prior to the 3-day environmental treatment period. Body weight was recorded on day -1 and day 3 relative to start of environmental treatment. Body temperature (BT) and respiration rate (RR) were measured thrice daily and feed intake (FI) were recorded daily. Blood samples were collected on day -1 and day 3 to determine metabolite profiles and immune response. Following sacrifice, sections of duodenum, ileum, and colon were collected for histology. Pigs in HS conditions had increased average BT and RR (~2.7-fold) compared to TN and PFTN groups (P<0.01). Irrespective of day, HS+ animals had increased respiration rates when compared to HS- animals (P<0.04). Heat stress decreased FI compared to TN groups. Regardless of treatment, supplement increased feed efficiency by 0.12kg (P<0.04). Circulating glucose concentration tended to decrease in HS+ and PFTN+ pigs compared to non-supplemented treatments (P=0.1). Circulating insulin increased in HS compared to PFTN (P<0.04), but did not differ from TN. Lymphocyte count tended to be decrease in HS compared to PFTN and TN (P=0.052). Monocyte count increased during HS compared to PFTN (P=0.01), but HS and TN did not differ. Supplement increased basophil count (P<0.03), irrespective of treatment. Ileal villus height tended to decrease during HS and PFTN compared to TN (P<0.08). Duodenal and colon villus height nor duodenal, ileal and colon crypt cell depth did not differ between groups. Overall, TakTik Sweet Heat supplementation increases pig feed efficiency and may improve immune response. === Master of Science
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