EFFECT OF EXOGENOUS ENZYMES AND A NOVEL GLP2 ON GUT HEALTH AND GROWTH PERFORMANCE
Creators: name: Asmus, Matthew Duane
Publisher: name: Purdue University Graduate School
Year: 2022
Subjects: Animal nutrition

description: We have a need to increase protein production as the world population continues to increase. Seeing that land and resources are a limited commodity, the need to raise pigs as efficiently as possible will continue to increase. Similarly, as the industry switches further away from antibiotics and growth performance technologies, the need for wholistic alternatives continues to increase. Therefore, the focus of this dissertation primarily focuses on technologies to improve pig growth performance both in the nursery (Chapter 3 and 4) as well as the finisher (Chapter 2 and 3). In chapter two, two experiments were conducted to evaluate the effect of β-mannanase and lysine level as well as β-glucanase and β-mannanase in combination during ractopamine feeding prior to market. In Exp. 1, 343 crossbred pigs were blocked by ancestry, sex, and initial BW (97.3 ± 1.36 kg) and allocated to mixed gender pens (5 or 6 pigs/pen) to 5 treatments with 10 or 12 pens/treatment. Dietary treatments included: 1) low lysine (0.80% SID Lys; LL); 2) LL+mannanase (0.08 MU/kg); 3) high lysine (0.95% SID Lys; HL); 4) HL+mannanase (0.08 MU/kg); 5) As treatment 3 + 4% choice white grease (CWG). Diets were corn-soy based (LL and HL=3335 and CWG=3517 kcal ME/kg) and contained 7.5 ppm ractopamine. One pig/pen was harvested on d 7 and 21, with remaining pigs harvested on d 35. For d 7-21 and 0-35 pigs fed the HL diets tended (<em>P</em>&lt;0.06) to have improved G:F compared to pigs fed LL diets. For d 21-28 (<em>P</em>&lt;0.03) and 0-35 (<em>P</em>&lt;0.03) pigs fed LL diets had greater ADFI than pigs fed HL diets. Pigs fed mannanase tended to have increased ADFI (<em>P&lt;</em>0.06) d 21-28 and improved (<em>P&lt;</em>0.10) ADG (984 vs 937 g/d) from d 21-35. Pigs fed the CWG diet had improved ADG (<em>P</em>&lt;0.04) from d 21-35 and 0-35 and for periods d 7-21 (<em>P</em>&lt;0.01) and 0-35 (<em>P</em>&lt;0.07) had reduced ADFI compared to pigs fed the HL diet. This resulted in improved G:F (<em>P&lt;</em>0.01) from d 14-21, 21-28, 7-21, 21-35, and 0-35. Pigs harvested on d 7 fed mannanase diets had increased (<em>P&lt;</em>0.01) carcass yield and tended to have increased (<em>P&lt;</em> 0.06) loin depth, but reduced yield (<em>P&lt;</em>0.06) on d 21. Pigs fed LL diets had increased (<em>P&lt;</em>0.05) backfat (BF) depth compared to pigs fed HL diets on d 7. Pigs fed HL diets harvested on d 21 had reduced (<em>P&lt;</em>0.01) BF depth and increased (<em>P&lt;</em>0.03) percent lean versus pigs fed LL diets. Pigs fed CWG had increased (<em>P&lt;</em>0.02) BF depth d 21 and d 35 and reduced (<em>P&lt;</em>0.03) percent lean d 21 compared to pigs fed the HL diet. Overall, pigs fed HL diets had reduced (<em>P&lt;</em>0.04) BF depth and tended to have increased (<em>P&lt;</em>0.08) percent lean when compared to pigs fed LL and CWG diets. A second experiment was then designed to evaluate β-mannanase with and without β-glucanase in combination with ractopamine feeding. One-hundred eighty pigs (initial BW=105.4 ± 1.29 kg) were used to evaluate the effects of two enzymes individually and in combination in a corn-soybean meal-cDDGS based diet on pig growth performance and feed efficiency during late finishing. Pigs were allocated in a randomized complete block design of mixed gender pens, stratified by ancestry, gender, and initial BW to 5 treatments with 6 pens/treatment and 6 pigs/pen. Dietary treatments included: 1) negative control (0.75% SID Lys; NC); 2) NC plus ractopamine (RAC); 3) RAC+mannanase (0.08 MU/kg β-mannanase; RENZ1); 4) RAC+enzymes (0.08 MU/kg β-glucanase + 0.10 MU/kg β-mannanase; RENZ2); 5) RAC+enzymes (0.08 MU/kg β-glucanase, 0.18 MU/kg β-mannanase; RENZ1+2). Treatments 2-5 contained 5 ppm ractopamine from d 0-14 and 10 ppm ractopamine from d 14-28. For d 0-14, pigs fed the RAC diet had increased (<em>P</em>&lt;0.003) ADG, improved feed efficiency and tended (<em>P</em>&lt;0.06) to have increased ADFI when compared to pigs fed the NC diet. Pigs fed RENZ1 had increased (<em>P</em>&lt;0.05) ADG, and improved (<em>P</em>&lt;0.02) G:F, while pigs fed RENZ2 tended (<em>P</em>&lt;0.08) to have reduced G:F compared to pigs fed RAC. Pigs fed RAC from d 14-28 had increased (<em>P</em>&lt;0.05) ADG, ADFI, and improved G:F compared to NC. Feeding RENZ1, RENZ2, or RENZ1+2 had no impact (<em>P&gt;</em>0.22) on ADG, ADFI, or G:F from d 14-28 compared to RAC fed pigs. For the overall period d 0-28, pigs fed RAC diets had increased (<em>P</em>&lt;0.04) ADG and ADFI with improved (<em>P</em>&lt;0.001) feed efficiency compared to NC. Pigs fed RENZ1 had increased (<em>P</em>&lt;0.02) ADG and improved (<em>P</em>&lt;0.01) feed efficiency while pigs fed RENZ2 had no improvement (<em>P&gt;</em>0.21) in measured response criteria compared to pigs fed RAC. Pigs fed RAC had increased (<em>P&lt;</em>0.01) final live BW, carcass weight, loin depth, fat free lean, and value per pig. In conclusion, pigs fed the RAC diet had increased ADG and ADFI with improved feed efficiency throughout the trial. Pigs fed RAC + mannanase had increased ADG resulting in improved feed efficiency compared to pigs fed RAC. Chapter 3 focused on one experiment split over two growth periods was conducted to evaluate the effect of saccharomyces cerevisiae or lactobacillus acidophilus fermentation products (SCFP and LAFP, respectively) and vaccination for <em>Mycoplasma hyopneumoniae</em> and Porcine circovirus type 2 on growth performance, serum immune markers, and intestinal villi height. In period 1, 135 pigs [Duroc × (Yorkshire × Chester); initially 5.75 ± 0.51 kg BW] were blocked by ancestry, sex, and initial BW (6 blocks) and assigned to mixed gender pens (4 or 5 pigs/pen) to 5 treatments with 6 pens/treatment. Treatments included: 1) Negative control (NC), control diets, non-vaccinated no added fermentation products; 2) Positive control (PC), control diets, vaccinated, no added fermentation products; 3) PC + SCFP (0.2% d 0-21, 0.1% d 21-56); 4) PC + LAFP (0.1% d 0-21, 0.05% d 21-56; LAFP-Low); 5) PC + LAFP (0.2% d 0-21, 0.1% d 21-56; LAFP-High). Diets were corn-soy based. Two gilts and one barrow per pen were repeatedly bled every 7 days from d 0-35. One of the identified bleeding gilts per pen was selected to be sacrificed on d 33 of the trial for intestinal tissue sample collection. For d 7-14 NC (<em>P&lt;</em>0.05) pigs had improved G:F compared to all other vaccinated pigs. For d 14-21 (<em>P&lt;</em>0.03), d 21-28 (<em>P&lt;</em>0.05, d 28-35 (<em>P&lt;</em>0.09), and d 0-35 (<em>P&lt;</em>0.02) vaccinated pigs had increased ADFI and tended to have improved ADG (<em>P&lt;</em>0.09) from d 14-21 compared to NC pigs. Similarly, from d 0-35 PC pigs tended (<em>P&lt;</em>0.09) to have increased ADFI when compared to NC pigs. Villus height d 33 tended (<em>P&lt;</em>0.07) to be reduced when pigs were vaccinated vs the NC. For d 35 all vaccinated pigs tended (<em>P&lt;</em>0.10) to have increased TNF-α vs NC. On d 28 a larger percentage of LAFP-High pigs tested positive (<em>P&lt;</em>0.01) for circovirus. On d 35 a higher percentage of NC pigs tested negative (<em>P&lt;</em>0.001) for circovirus. During the nursery period mycoplasma optical density (MOD) was lower (<em>P&lt;</em>0.05) for LAFP-Low and High than vaccinated PC while mycoplasma sample to positive (S/P) ratio tended (<em>P&lt;</em>0.08) to be lower in LAFP-Low and High vs vaccinated PC. During the nursery period MOD and S/P ratio increased (<em>P&lt;</em>0.001) more on d 14 than d 21, d 28, or d 35. During the nursery period circovirus titers were significantly increased (<em>P&lt;</em>0.03) for all vaccinated pigs vs NC. Both LAFP-Low and LAFP-High pigs had increased (<em>P&lt;</em>0.001) circovirus titer compared to PC and SCFP. During the nursery period circovirus titers were lower (<em>P&lt;</em>0.05) on d 14 and d 28 vs d 21 and d 35. Circovirus titer results during the nursery period were reduced for NC (<em>P&lt;</em>0.004) when compared to all other vaccinated groups. During the nursery period circovirus titer results were higher (<em>P&lt;</em>0.001) on d 21 than d 14 &amp; d 28, and higher (<em>P&lt;</em>0.01) on d 35 than on d 21. In period 2 of the trial, 90 remaining pigs (initially 18.63 ± 1.50 kg BW) were combined by nursery treatment and assigned to mixed gender pens (6 pigs/pen) with 3 pens/treatment. During this grow-finish period, nursery treatments continued from d 35 to 56 post-weaning. After d 56 the control treatments continued, and the fermentation product treatments were fed SCFP: 3) SCFP (0.1% SCFP d 56-market); 4) LAFP-Low (0.1% SCFP d56-market); 5) LAFP-High (0.2% SCFP d 56-market). Diets were corn-soy based during this grow-finish period. From d 56-77 the main effect of vaccination tended (<em>P&lt;</em>0.08) to increase ADFI while worsening G:F (<em>P&lt;</em>0.06). As a result, overall (d35-market) ADFI tended (<em>P&lt;</em>0.07) to be increased when pigs were vaccinated. During the grow-finish period MOD, mycoplasma S/P ratio, mycoplasma sample result, circovirus titer, and circovirus titer result all were reduced (<em>P&lt;</em>0.0001) when pigs were not vaccinated. Similarly, the main effect of day had significant impact on all blood criteria measured throughout the grow-finish portion of the trial, however there were interactive effects for mycoplasma titer result (<em>P&lt;</em>0.005) were non vaccinated pigs showed lower titer results from d 56 to 98 when compared to vaccinated pigs, then had 100% positives, the same as vaccinated pigs. Similarly, there was a treatmentxday interaction in the grow-finish period for circovirus titer, where non vaccinated pigs started negative and remained negative throughout the trial, while vaccinated pigs started with 100% having a titer then declined by day 119 and 140 to 50-75% positive. <br> <br>