Pigs experience biological stress such as physiological, environmental, and social challenges when weaned from the sow. The process of weaning is one of the most stressful events in the pig’s life that can contribute to intestinal and immune system dysfunctions that result in reduced pig health, growth, and feed intake, particularly during the first week after weaning. Technological improvements in housing, nutrition, health, and management have been used to minimize some of the adverse effects of weaning stress, but a greater understanding of the biological impact of stress is needed to improve strategies to overcome weaning stress. The focus of this review paper is to briefly describe how the biological stress associated with weaning impacts intestinal morphology, structure, physiology, and intestinal immune responses that can impact subsequent production efficiencies such as growth, intake, morbidity, and mortality.

Spray-dried plasma (SDP) is a functional ingredient commonly utilized in swine production and calf milk replacers to improve performance, feed efficiency, and health. The improvements noted with SDP in animal production are more pronounced under commercial production conditions compared to cleaner research settings. Multiple modes of action of SDP have been proposed, including either directly influencing the immune inflammatory response locally or systemically, and/or through the indirect modification of beneficial microbial populations. Spray-dried plasma included at various dietary levels and duration of feeding in broilers has been evaluated in different production and challenging conditions with beneficial effects on broiler performance, as noted in other animals. The purpose of this review is to discuss research related to the modes of action of SDP on immunomodulation and improved intestinal health and specifically discuss research conducted utilizing SDP in feed for poultry. Collectively, the data available indicates that SDP improves early intestinal health and supports an efficient immune system response both locally at the intestine and systemically, thereby benefiting growth, feed efficiency, and survival of broilers in conventional commercial production and under challenging conditions such as disease or environmental stressors.

Conventional vaccination programs using a single injection of a combined vaccine against porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (MHYO) can promote a strong immune response that reduces feed intake for 24 to 48 h post injection. Often such vaccines are given around the time of weaning during a critical stress period in which feed intake is already compromised. Spray dried porcine plasma (SDPP) is a protein source used in starter diets that increases post-weaning feed intake of pigs. The objectives of this study were to determine the effects of a conventional vaccination program along with feeding SDPP in a starter diet on antibody development and wean to finish performance of pigs. Pigs fed the starter diet with SDPP had improved body weight, average daily weight gain and average daily feed intake during the initial 14 d after weaning along with improved feed efficiency during the initial 7 d after weaning and these responses were independent of vaccination. Vaccination at 3 d after weaning had no significant effect on performance during the initial 14 d after weaning. Cumulative mortality was reduced for pigs fed the starter diet with SDPP, while vaccinated pigs had reduced mortality from d 48 to 145. Both vaccinated pigs and those fed the starter diet with SDPP had heavier carcass weight. One pig per pen was challenged with PCV2 at d 63. A higher percentage of vaccinated pigs were sero-positive for antibodies against PCV2 and MHYO at d 35, 63 and 78. Antibody values against PCV2 were higher for vaccinated pigs at d 35 and 63, but lower at d 146. Percentage of positive samples for PCV2 genome in serum was reduced for vaccinated pigs at d 117 and 146. Antibody values against MHYO were increased for vaccinated pigs at d 35, 63 and 78. Vaccination supported a long term antibody response against PCV2 and a moderate but weaker antibody response against MHYO for early finishing pigs challenged with PCV2. Using SDPP in the starter diet along with vaccination supported the best long-term beneficial effects on survival to market and carcass weight.

Hepatitis E virus (HEV) has been reported in the human population and pigs are a recognized reservoir for HEV and a possible source of HEV transmission to humans. Spray-dried porcine plasma (SDPP) is an ingredient commonly used in feed for pigs around the world. Even though processing conditions used to produce SDPP should be adequate to inactivate HEV, it was of interest to analyze commercial SDPP samples for presence of genome and antibodies (AB) against HEV and to retrospectively analyze serum samples collected from pigs used in past experiments that had been fed diets containing either 0% or 8% SDPP to detect potential transmission of HEV as determined by seroconversion. Eighty-five commercial SDPP samples were analyzed by ELISA and 100% of them contained AB against HEV, while 22.4% (11 of 49 samples analyzed) were positive for HEV RNA. Frozen sera samples (n = 140) collected from 70 pigs used in past experiments that had been fed diets containing either 0% or 8% commercial SDPP was analyzed by ELISA for AB against HEV. Age of pigs at sera sampling ranged from 3 to 15 weeks and feeding duration of diets ranged from approximately 4 to 9 weeks. One lot of SDPP used in one experiment was analyzed and confirmed to contain HEV RNA. Regardless of the diet fed, some sera samples collected at the beginning of an experiment contained AB titer against HEV. These sera samples were collected from weaned pigs prior to feeding of the experimental diets and the HEV titer was probably from maternal origin. However, by the end of the experiments, HEV titer was not detected or had declined by more than 50% of the initial titer concentration. To our knowledge, this is the first study reporting presence of HEV AB titer and RNA in SDPP. Retrospective analysis of serum collected from pigs fed diets with SDPP revealed no indication of seroconversion to HEV. The results indicate that feeding SDPP in diets for pigs does not represent a risk of transmitting HEV, even though HEV genome may be detected in SDPP.

Stress causes inflammation that impairs intestinal barrier function. Dietary spray-dried plasma (SDP) has recognized anti-inflammatory effects and improvement of gut barrier function. Therefore, the purpose of this study was to investigate the effects of dietary SDP on intestinal morphology of mated female mice under stress condition. Villus height, width, and area of small intestines were low on gestation day (GD) 3 or 4 under stress conditions, and higher later (Time, P < 0.05). Crypt depth of colon was low on GD 4 and higher later (Time, P < 0.05). Meanwhile, the SDP treatments improved (P < 0.05) intestinal morphology, indicated by increased villus height, villus width, villus area, and ratio between villus height and crypt depth of small intestines and crypt depth of colon, and by decreased crypt depth of small intestines, compared with the control diet. The SDP treatments also increased (P < 0.05) the number of goblet cells in intestines compared with the control diet. There were no differences between different levels of SDP. Dietary SDP improves intestinal morphology of mated female mice under stress condition.

Absorption of energy and IgG at birth from colostrum may improve survival and immune competency of newborn piglets. Adequate intake of colostrum may be difficult for piglets due to low birth weight, birth order, or viability. This study was designed to evaluate orally fed colostrum supplements with different energy sources and IgG from porcine plasma on piglet serum IgG content and absorption of IgG compared to pooled sow colostrum. Ninety-six newborn piglets from 12 sows with an average birth weight of 1,288 g were used. Eight piglets were removed from each sow immediately at birth, prior to suckling, and randomly allotted to receive either pooled sow colostrum or 1 of 3 colostrum supplements (A, B, and C) fed at 2 dosing schemes. Piglets received their allotted treatment as either one 30-mL dose at 0 h or three 10-mL doses at 0, 2, and 4 h. Piglets received ad libitum access to water at 2-h intervals after receiving their last treatment dose. Twelve hours after the first dose, piglets were weighed and 4 mL of blood was collected. Plasma IgG content, apparent efficiency of absorption, hematocrit, protein, and glucose were determined. Birth weight and final BW did not differ between treatments; however, pigs fed sow colostrum lost more weight (–72 g) than pigs fed colostrum supplements (–40 g; P < 0.001). Differences in hematocrit or serum glucose were not detected. Serum protein was higher (P < 0.05) in piglets fed colostrum supplements than in pigs fed sow colostrum. Serum IgG content did not differ among treatments. Apparent efficiency of IgG absorption was greatest for sow colostrum followed by colostrum supplements B, A, and C (28.5, 27.6, 25.5, and 24.7%, respectively). The single and multiple dose regimes delivered comparable serum IgG whereas the single dose yielded better piglet hydration as noted by less weight loss. In conclusion, all colostrum supplements were comparable in delivering absorbable IgG to the neonatal piglet. Copyright © 2013. American Society of Animal Science .