I. Park

Effects of feed grade l-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional dl-methionine

This study was conducted to test the effects of supplemental L-Met on redox status, gut development, and growth performance of young broiler chickens compared with DL-Met. A total of 888 (half male and half female) 1-d-old Ross 308 chickens were weighed and randomly allotted to 7 treatments in a randomized complete block design for 21 d, including a basal diet (BD), the BD + 0.095% L-Met or DL-Met, the BD + 0.190% L-Met or DL-Met, and the BD + 0.285% L-Met or DL-Met (representing 60, 70, 80, and 90% of the Met + Cys requirement). Feed disappearance and BW were recorded every 7 d. Liver and duodenum samples were collected on d 0, 7, and 21 to measure redox status and intestine morphology. On d 7, chicks fed a diet supplemented with either 0.285% L-Met or 0.285% DL-Met had increased (P < 0.05) concentrations of glutathione (GSH) and reduced (P < 0.05) protein carbonyl (PC) and malonedialdehyde contents in duodenum mucosa compared with chicks fed the BD. Chicks fed a diet supplemented with 0.285% L-Met had greater (P < 0.05) villus width compared with chicks fed a diet supplemented with 0.285% DL-Met. Chicks fed a diet supplemented with 0.285% L-Met had lower (P < 0.05) crypt depth and greater (P < 0.05) villus height:crypt depth ratio compared with chicks fed a diet supplemented with 0.285% DL-Met or the BD. On d 21, chicks fed a diet supplemented with 0.285% L-Met had increased (P < 0.01) concentrations of GSH and total antioxidant capacity (TAC) but reduced (P < 0.05) PC content in duodenum mucosa compared with chicks fed a diet supplemented with 0.285% DL-Met and the BD. Chicks fed a diet supplemented with 0.285% L-Met had greater (P < 0.05) villus height compared with chicks fed the BD. During the entire 21-d supplementation of either L-Met or DL-Met, ADG and G:F were enhanced (P < 0.01) compared with chicks fed the BD. Chicks fed diets supplemented with L-Met had greater (P < 0.05) ADG and G:F than chicks fed diets supplemented with DL-Met. The relative bioavailability of L-Met to DL-Met for ADG and G:F was 138.2 and 140.7%, respectively. Overall, supplementation of either L-Met or DL-Met has beneficial effects on villus development in association with increased GSH production and levels of TAC and reduced protein oxidation in duodenum. Supplementation of L-Met served a better function on redox status and development of the gut of chicks compared with DL-Met. Chicks fed diets with L-Met had better growth response than chicks fed diets with DL-Met.

Effect of dietary supplementation of xylanase on apparent ileal digestibility of nutrients, viscosity of digesta, and intestinal morphology of growing pigs fed corn and soybean meal based diet

This study was to determine apparent ileal digestibility of acid detergent fiber (ADF), neutral detergent fiber (NDF), dry matter (DM), energy, organic matter (OM), crude ash, digesta viscosity, and gut morphology in nursery pigs fed diets containing xylanase (Lohmann Animal Nutrition GmbH, Cuxhaven, Germany). The diet (61% corn, 35% soybean meal, 1% poultry fat, and 3% minerals and vitamins) was mixed with 3 levels of xylanase (0, 700, and 1400 LXU/kg). Thirty-six barrows (17.6 ± 3.3 kg) received one of 3 treatment diets based on a randomized complete block design with the initial body weight (BW) as a block. Pigs were individually housed and received experimental diets twice daily (0700 and 1700 h) at a fixed amount based on BW of pigs (0.09 × BW0.75 kg). Pigs were fed diets for 10 d, and chromium oxide (0.3%) was added to the diets from d 6 as an indigestible external marker. Pigs were euthanized at the end of d 10 for the collection of digesta and tissues. Jejunal digesta were centrifuged to measure viscosity using a viscometer (Brookfield Engineering Laboratories, Stoughton, MA). Diets and freeze-dried ileal digesta were used to measure ADF, NDF, and chromium to calculate apparent ileal digestibility of ADF and NDF. Villus height and crypt depth of jejunum were measured using a microscope (Fisher Scientific, Hampton, NH). Data were analyzed using polynomial contrasts in the MIXED procedure of SAS version 9.3 (SAS Inc., Cary, NC, USA). Morphological measurements and ileal ADF digestibility were not affected by increasing xylanase. However, increasing xylanase supplementation from 0 to 1400 LXU/kg enhanced ileal digestibility of NDF (P < 0.042, linear) from 27.9 to 40.3%, DM (P < 0.006, linear) from 55.4 to 64.6%, OM (P < 0.006, linear) from 59.2 to 67.7%, and energy (P < 0.003, linear) from 58.8 to 68.0%. Viscosity of jejunal digesta decreased (P < 0.023) in a non-linear manner from 2.9 to 2.5 centipoises (cP). In conclusion, the usage of xylanase in corn and soybean meal based pig diets linearly enhanced digestibility of nutrients and affected viscosity of digesta in a non-linear manner.

Impacts of low level aflatoxin in feed and the use of modified yeast cell wall extract on growth and health of nursery pigs

This study was to investigate the effect of corn naturally contaminated with aflatoxins (AF) under the regulatory level on the growth performance and health of nursery pigs, and the efficiency of yeast cell wall based feed additive (YC) mainly composed of β-glucans and mannan oligosaccharide (MOS) (Integral A+, Alltech, Lexington, KY) in prevention of mycotoxicosis. Pigs (60 barrows and 60 gilts at 6.02 ± 0.83 kg BW) were randomly allotted to 4 treatments in a randomized complete block design based on a 2 × 2 factorial arrangement with 10 pens (5 barrow and 5 gilt pens) per treatment and 3 pigs per pen. Pigs were fed experimental diets for 5 wk. First factor was AF (0 or 20 µg/kg in feed) and the second factor was YC (0 or 2 g/kg in feed). Feed intake and body weight were measured weekly, and blood samples were used to measure blood cell counts, immunoglobulin G (IgG), tumor necrosis factor-a (TNF-a), oxidative damage status, and serological evaluation related to liver health. Aflatoxin decreased (P < 0.05) the number of platelet count (247.4 to 193.5 × 103/µL), and it also tended to increase the level of albumin (P = 0.055, 3.46 to 3.63 g/dL), albumin:globulin ratio (P = 0.050, 2.09 to 2.37), and Ca (P = 0.080, 10.79 to 10.97 mg/dL). Yeast cell wall based feed additive increased (P < 0.05) ADG (493 to 524 g/d), and ADFI (796 to 846 g/d) of pigs whereas G:F was not affected, and it also tended to increase (P = 0.055) albumin level (3.46 to 3.63 g/dL). Interactions (P < 0.05) on hemoglobin, hematocrit, and platelet count indicated that YC further increased their levels when pigs were eating AF contaminated feed. Interactions (P < 0.05) on urea nitrogen and blood urea N to creatinine ratio indicated that YC further decreased their levels when feed were contaminated with AF. In conclusion, low level of 20 µg AF/kg under the regulatory level had minor effects on hematology without affecting growth performance, however the supplementation of 2 g/kg YC as a source of β-glucans and MOS in feed can improve feed intake and therefore the growth of pigs.

Impacts of energy feeds and supplemental protease on growth performance, nutrient digestibility, and gut health of pigs from 18 to 45 kg body weight

A total of 144 pigs with 18.4 ± 2.3 kg initial body weight (BW) at 6 wk of age were used in a 40-d trial to evaluate effects of protease (300,000 U/kg feed, BioResource International Inc., Durham, NC, USA) on growth performance, apparent ileal digestibility (AID) of nutrients, and gut health of pigs fed diets with sorghum. Pigs were randomly allotted to 4 treatments (12 pens per treatment, 3 pigs per pen) in a 2 × 2 factorial arrangement (corn or sorghum basal diets, and 0 or 0.05% protease as 2 factors) with sex and initial BW as blocks. Experimental period had phase 1 (d 1 to 21) and phase 2 (d 22 to 40). About 65% (phase 1) and 72% (phase 2) of cereal grains were used in corn or sorghum based diets. Both grains were ground to 400 μm. Body weight and feed intake were recorded weekly. On d 35, serum was collected to quantify tumor necrosis factor-α (TNF-α) and malondialdehyde (MDA). Titanium dioxide (0.3%) was added as an indigestible marker for an additional 4 d feeding. On d 40, 32 pigs (8 pigs per treatment) were euthanized to collect digesta from jejunum and ileum (for viscosity and AID), tissues (for morphology) and mucosa samples (for TNF-α and MDA) from duodenum, jejunum, and ileum. Replacing corn with sorghum in the diet increased (P < 0.05) overall average daily gain (from 756 to 787 g/day) and average daily feed intake (from 1,374 to 1,473 g/day), reduced (P < 0.05) overall gain:feed ratio (from 0.553 to 0.537), and did not affect AID. Pigs fed diets with sorghum had lower (P < 0.05) MDA content in serum (from 14.61 to 6.48 μmol/L) and jejunum (from 1.42 to 0.91 μmol/g protein), and reduced (P < 0.05) villus height (from 492 to 396 μm) and crypt depth (from 310 to 257 μm) in jejunum. Dietary protease improved (P < 0.05) AID of crude protein (from 81.8% to 86.0%), decreased MDA level (from 1.20 to 0.98 μmol/g protein) in duodenum, and increased (P < 0.05) the ratio of villus height to crypt depth (from 1.08 to 1.21) in duodenum. Overall, use of sorghum fully replacing corn in diets could benefit pigs with enhanced growth and feed intake potentially by reducing oxidative stress, whereas feed efficiency was compromised. Supplementation of protease improved protein digestion and maintained gut health, irrespective of sorghum or corn based diets.