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.

The objective of this study was to evaluate the effectiveness of the SurePure Turbulator ultraviolet-C (UV-C, 254 nm wavelength) irradiation equipment on inactivation of different enveloped and non-enveloped viruses in commercially collected liquid animal plasma. Specifically, Pseudorabies virus (PRV), Porcine reproductive and respiratory syndrome virus (PRRSV), Porcine epidemic diarrhea virus (PEDV), Bovine viral diarrhea virus (BVDV), Classical swine fever virus (CSFV), Swine influenza virus (SIV) as enveloped viruses and Porcine parvovirus (PPV), Swine vesicular disease virus (SVDV), Porcine circovirus type 2 (PCV-2) and Senecavirus A (SVA) as non-enveloped viruses, were inoculated in bovine or porcine plasma and subjected to different UV-C irradiation doses (0, 750, 1500, 3000, 6000 and 9000 J/L) using an UV-C device developed for opaque liquid working under turbulent flow. The enveloped viruses tested were inactivated at < 3000 J/L of UV-C, being the dose needed to inactivate 4 log TCID₅₀ (4D) of 1612 J/L for PRV,1004 J/L for PRRSV, 1953 J/L for PEDV, 1639 J/L for SIV, 1641 J/L for CSFV and 1943 J/L for BVDV. The non-enveloped viruses tended to have higher 4D values: 2161 J/L for PPV, 3223 J/L for SVA and 3708 J/L for SVDV. Because the initial viral concentration was <4.0 Log for PCV-2, it was not possible to calculate the 4D value for this virus. In conclusion, these results demonstrated that the SurePure Turbulator UV-C treatment system is capable of inactivating significant levels of swine viruses inoculated in commercially collected porcine or bovine plasma. It was concluded that irradiation with UV-C can provide an additional redundant biosafety feature in the manufacturing process of spray-dried animal plasma.

The objective of this study was to determine if commercially collected liquid porcine plasma contaminated with African swine fever virus (ASFV) and fed for 14 consecutive days would infect pigs. Commercially collected liquid porcine plasma was mixed with the serum from an ASFV experimentally infected pig. To simulate the potential of pigs slaughtered being ASFV viremic but asymptomatic and passing antemortem inspection, the ratio of liquid plasma from healthy animals to serum from an ASFV infected pig used in this study represented 0.4% or 2.0% of the pigs slaughtered being viremic (Studies 1 or 2, respectively). The contaminated liquid plasma was mixed on commercial feed and pigs were fed for 14 consecutive days providing to each pig 10^4.3 or 10^5.0 TCID₅₀ ASFV daily (Studies 1 or 2, respectively). Pigs were observed for an additional 5 or 9 days (Studies 1 or 2, respectively). In both experiments, the pigs did not become infected with ASFV during the 14d feeding period or during the subsequent observation period. In these experiments, unprocessed liquid plasma contaminated with ASFV mixed on commercial feed and fed for 14 consecutive days did not infect pigs. From our results we can conclude that the infectious dose of ASFV on feed is much higher than that previously reported, at least with ASFV-spiked raw plasma.

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.

SUMMARY. Two experiments were conducted to evaluate the effect of titrated levels of spray-dried plasma (SDP) in broilers diets submitted to various types of h