The effects of standardized ileal digestible His to Lys ratio on growth performance, intestinal health, and mobilization of histidine-containing proteins in pigs at 7 to 11 kg body weight.

The objectives were to evaluate the effects of standardized ileal digestible (SID) His:Lys ratio above the current NRC requirement on growth performance, intestinal health, and mobilization of His-containing proteins, including hemoglobin, carnosine, and trypsinogen, in nursery pigs from 7 to 11 kg body weight (BW). Forty pigs (26 d of age; initial BW of 7.1 ±â€…0.5 kg) were allotted to 5 dietary treatments based on a randomized complete block design with sex and initial BW as blocks. Dietary treatments were supplemented with varying SID His to Lys ratios of 26%, 32%, 38%, 43%, and 49% and fed to pigs for 14 d (SID Lys = 1.22%). Feed intake and BW were recorded at d 0, 7, and 14 to measure growth performance. Blood samples were collected on d 12. Pigs were euthanized on d 14 to collect pancreas, longissimus dorsi muscles, mid-jejunum, and jejunal mucosa. Data were analyzed using the Proc Mixed of SAS. Growth performance was not affected, whereas varying SID His to Lys ratio affected hemoglobin (P < 0.05, max: 12 g/dL at 36%), immunoglobulin A (IgA, P < 0.05, min: 1.25 µg/mg at 35%) in jejunal mucosa, villus height (P = 0.065, max: 536 µm at 40%) in jejunum, trypsinogen (P = 0.083, max: 242 pg/mg at 41%) in pancreas, and carnosine (P = 0.051, max: 4.7 ng/mg at 38%) in muscles. Varying SID His to Lys ratios linearly increased (P < 0.05, from 1.95 to 2.80 nmol/mg) protein carbonyl in muscles and decreased (P < 0.05, from 29.1% to 26.9%) enterocyte proliferation. In conclusion, SID His to Lys ratio between 35% and 41% in diets fed to nursery pigs at 7 to 11 kg enhanced intestinal health and maximized concentrations of His-containing proteins, indicating that His-containing proteins are effective response criteria when determining His requirement.

Histidine is an essential amino acid for protein synthesis, but it also plays a vital role in the metabolic system of pigs. An accurate assessment of His requirement provides pivotal information for efficient growth and health of pigs. Growth performance and plasma His concentration have been used to assess His requirement, but they may not be the effective parameters due to the contribution of His from mobilization of His-containing proteins, such as hemoglobin, carnosine, and pancreatic enzymes. Hemoglobin is a transport protein and the main component in red blood cells, enabling oxygen transport throughout the body. Most carnosine is stored in muscles at 3 to 4 g/kg wet weight and has antioxidative effects to prevent cells from oxidative damages. In addition, His has a critical role in serine peptidases as a part of the catalytic triad. In this study, growth performance did not respond to His deficiency due to the compensation of His from His-containing proteins and potentially due to a short experimental period. Standardized ileal digestible His to Lys ratio between 35% and 41% maximized concentrations of His-containing proteins and enhanced intestinal health in pigs at 7 to 11 kg body weight. This study indicated that hemoglobin, carnosine, and trypsinogen are effective response criteria when determining His requirement.

Nutritional and functional values of lysed Corynebacterium glutamicum cell mass for intestinal health and growth of nursery pigs.

The objective was to determine the nutritional and functional values of lysed Corynebacterium glutamicum cell mass (CGCM) as a protein supplement and a source of cell wall fragments supporting the growth and intestinal health of nursery pigs. Thirty-two pigs (21 d of age) were allotted to four treatments (n = 8) based on the randomized block design with sex and initial body weight (BW) as blocks. The main effect was the dietary supplementation of lysed CGCM (0, 0.7, 1.4, and 2.1%) replacing blood plasma and fed in two phases (10 and 11 d, respectively). Feed intake and BW were measured at the end of each phase. Pigs were euthanized on day 21 to collect jejunal tissue and mucosa to evaluate intestinal health. Ileal digesta were collected to measure the apparent ileal digestibility of nutrients in diets. Data were analyzed using Proc Mixed and Reg of SAS. Increasing daily intake of CGCM increased (linear; P < 0.05) ADG of pigs. Increasing CGCM supplementation affected (quadratic; P < 0.05) the relative abundance of Lactobacillaceae (minimum: 26.4% at 1.2% CGCM), Helicobacteraceae (maximum: 29.3% at 1.2% CGCM), and Campylobacteraceae (maximum: 9.0% at 1.0% CGCM). Increasing CGCM supplementation affected (quadratic; P < 0.05) the concentrations of immunoglobulin G (maximum: 4.94 µg/mg of protein at 1.0% CGCM) and protein carbonyl (PC; maximum: 6.12 nmol/mg of protein at 1.1% CGCM), whereas linearly decreased (P < 0.05) malondialdehyde (MDA) in the proximal jejunal mucosa. Increasing CGCM supplemention affected (quadratic; P < 0.05) intestinal enterocyte proliferation rate (maximum: 13.3% at 1.0% CGCM), whereas it did not affect intestinal morphology and the nutrient digestibility. In conclusion, supplementing 1.0% to 1.2%, reducing blood plasma supplementation by 0.7% to 0.9%, respectively, increased potential pathogenic microbiota associated in the jejunal mucosa resulting in increased immune response, enterocyte proliferation, and PC concentration. However, supplementing diets with 2.1% CGCM, replacing 1.5% blood plasma, improved growth performance, and reduced MDA without affecting nutrient digestibility, intestinal morphology, and microbiota in the jejunal mucosa. In this study, based on the polynomial contrast, supplementing 1.0% to 1.2% CGCM suppressed the benefits from blood plasma, whereas supplementing 2.1% CGCM showed functional benefits of CGCM with similar effects from blood plasma supplementation.