Contribution to the study of gut hypersensitivity reactions to soybean proteins in preruminant calves and early-weaned piglets

Evaluation of Soybean Ingredients in Pet Foods Applications: Systematic Review

Soybean use has been low in pet foods, even though they are an excellent source of protein, polyunsaturated fatty acids, and gut fermentable fibers. The purpose of this evaluation was to conduct a systematic review of the public literature to explore how soybeans have been researched for pet food applications since 2000 and to provide strengths, weaknesses, opportunities, and threats for soybeans in the pet food industry. The review covered a total of 44 articles related to soybean ingredients and their potential value in the pet food arena. The articles were categorized by their research contents and narratively summarized to demonstrate useful information to both the pet and soybean industries. When soybean-based products have been adequately processed to reduce the antinutritive factors, they are comparable to processed animal proteins in nutritional value, palatability, and functionality in pet food processing. We conclude that various food processing technologies and the versatility of soybean ingredients allow soybean to have considerable inclusion potential in pet foods. More research on dietary soybean ingredients regarding pet food processing, fermentation benefits on health, and consumer acceptance will be needed to understand soybean's position in the future pet food industry.

Effects of a new fermented soya bean meal on growth performance, serum biochemistry profile, intestinal immune status and digestive enzyme activities in piglets

BACKGROUND

Fermented soya bean meal (FSBM) is believed to have improved nutritional qualities compared with soya bean meal (SBM) and is also cheaper than soya protein concentration (SPC) and fish meal (FM). Therefore, the present study was conducted to compare the effects of FSBM replacing SBM, SPC and FM in diets on growth performance, serum biochemistry profile, short-chain fatty acid concentrations in digesta, intestinal mucosal enzyme activities, intestinal proinflammatory cytokine concentrations and morphology in weaned piglets. One hundred and twenty 28-day-old piglets (Duroc × Landrace × Yorkshire, body weight: 6.73 ± 1.14 kg) were randomly allocated to four treatment diets (six replicate pens with five piglets per pen) containing SBM, SPC, FM or FSBM as the protein source, respectively.

RESULTS

Dietary FSBM supplementation improved average daily gain (p < 0.05), gain to feed ratio (p < 0.05), and digestibility of dry matter, gross energy, crude protein and organic matter (p < 0.05) in pigs compared with those fed SBM during 0-14 days and reduced diarrhoea rate (p < 0.05) compared with those fed SBM and FM during 0-14 days. Moreover, pigs fed FBSM had greater IgA and IgM contents and antioxidase activities than those provided SBM and SPC on day 14. In addition, the butyrate concentration in the cecum of pigs fed FSBM was greater than those fed the other diets (p < 0.05), and the trypsin activity in duodenum and jejunum of pigs provided FSBM was greater than those fed SBM (p < 0.05). Moreover, higher villus height (p < 0.05) and villus height to crypt depth ratio (p < 0.05) and lower crypt depth (p < 0.05) in the duodenum of pigs fed FSBM were observed, and pigs fed FSBM had a lower (p < 0.05) TNF-α concentration in jejunum compared with those fed SBM.

CONCLUSIONS

In conclusion, dietary FSBM supplementation to replace SBM, SPC and FM could improve piglets' growth performance, intestinal health and immune function.

Acidic polypeptides A1a, A3 and A4 of Gly m 6 (glycinin) are allergenic for piglets

Gly m 6 (glycinin) is one of the major antigenic proteins in soybeans responsible for transient hypersensitivity to soybean meal in weaned piglets. The globulin is a hexamer consisting of subunits containing basic and acidic polypeptides. Multiple acidic polypeptides have long been demonstrated to be allergens for humans and play a key role in the overall allergenicity of Gly m 6. To date, knowledge on the allergenicity of the acidic polypeptides for piglets is very limited. The purpose of this study was to identify the acidic polypeptides that were allergenic for piglets and to characterize these acidic polypeptides by ELISA, western blot, skin prick and basophile histamine release test. The IgG and IgE antibody binding capacities of the acidic polypeptides of Gly m 6 were determined using ELISA and western blot analysis with sera from Gly m 6 sensitized piglets. Skin prick test and basophile histamine release test were conducted to measure the effector cell response to the polypeptides. Specific IgG and IgE antibodies against A_1a, A₃ and A₄ of Gly m 6 were identified in the sera of Gly m 6 sensitized piglets. Meanwhile, positive skin prick test and specific histamine release responses were also induced by the acidic polypeptide A_1a, A₃ and A₄ of Gly m 6 from the basophiles of Gly m 6 sensitized piglets. The results demonstrate that the acidic polypeptide A_1a, A₃ and A₄ of Gly m 6 are allergenic for piglets.

Changes of gut microbiota structure and morphology in weaned piglets treated with fresh fermented soybean meal

This study investigated the effects of dietary fresh fermented soybean meal (FSM) on the intestinal microbiota and metabolites, bacterial enzyme activity and intestinal morphology of weaning piglets. A total of 64 weaned piglets were randomly allocated into two treatments. A corn-soybean-based diet was used as the control and other treatment was fed the same basal diet containing 15% fresh FSM. The feeding trial lasted for 21 days. Bacterial community structure and diversity in the cecum and colon were assessed using pyrosequencing-based analysis. The results showed that the phylum level, Firmicutes, Bacteroidetes, Proteobacteria and Tenericutes were dominant in the cecum or colon. Gut Firmicutes increased, while Bacteroidetes and Proteobacteria decreased in the fresh FSM-fed piglets. At the genus level, the relative abundances of butyrate-producing bacteria, Lactobacillus and Prevotella were higher in both cecum and colon of fresh FSM fed piglets. Meanwhile, fresh FSM could promote the development of intestinal morphological and reduce the incidence of diarrhea. The results indicated that fresh FSM might change intestinal function by influencing intestinal microenvironment.

Maize 27 kDa gamma-zein is a potential allergen for early weaned pigs

Soybean and maize are extensively used in animal feed, primarily in poultry, swine, and cattle diets. Soybean meal can affect pig performance in the first few weeks following weaning and elicit specific antibodies in weaned piglets. Though maize is a major component of pig feed, it is not known if any of the maize proteins can elicit immunological response in young pigs. In this study, we have identified a prominent 27 kDa protein from maize as an immunodominant protein in young pigs. This protein, like some known allergens, exhibited resistance to pepsin digestion in vitro. Several lines of evidence identify the immunodominant 27 kDa protein as a gamma-zein, a maize seed storage protein. First, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of different solubility classes of maize seed proteins revealed the presence of an abundant 27 kDa protein in the prolamin (zein) fraction. Antibodies raised against the purified maize 27 kDa gamma-zein also reacted against the same protein recognized by the young pig serum. Additionally, matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the peptides generated by trypsin digestion of the immunodominant 27 kDa protein showed significant homology to the maize 27 kDa gamma-zein. Since eliminating the allergenic protein will have a great impact on the nutritive value of the maize meal and expand its use in the livestock industry, it will be highly desirable to develop maize cultivars completely lacking the 27 kDa allergenic protein.

Nutritional influences on some major enteric bacterial diseases of pig

There are several enteric bacterial diseases and conditions of pigs that require control to prevent overt disease, to reduce morbidity and mortality, and to improve the efficiency of production. Traditionally, veterinarians, feed manufacturers and producers have relied upon antibiotics and minerals (for example, ZnO, CuSO4) in diets for a large part of this control. However, recent trends, particularly in Europe, are to reduce antimicrobial use and seek alternative or replacement strategies for controlling enteric bacterial diseases. The majority of these strategies rely on 'nutrition', taken in its broadest sense, to reduce the susceptibility of pigs to these diseases. Evidence to date suggests that specific dietary interventions, for example feeding very highly-digestible diets based on cooked white rice, can reduce the proliferation of a number of specific enteric bacterial infections, such as post-weaning colibacillosis. No simple and universal way to reduce susceptibility to pathogens in the gastrointestinal tract has been identified, and the underlying basis for many of the reported positive effects of 'nutrition' on controlling enteric infections lacks robust, scientific understanding. This makes it difficult to recommend dietary guidelines to prevent or reduce enteric bacterial diseases. Furthermore, some diseases, such as porcine intestinal spirochaetosis caused by Brachyspira pilosicoli, are sometimes associated with other pathogens (co-infections). In such cases, each pathogen might have different nutrient requirements, ecological niches and patterns of metabolism for which a variety of dietary interventions are needed to ameliorate the disease. Greater understanding of how 'nutrition' influences gut epithelial biology and immunobiology, and their interactions with both commensal and pathogenic bacteria, holds promise as a means of tackling enteric disease without antimicrobial agents. In addition, it is important to consider the overall system (i.e. management, housing, welfare) of pig production in the context of controlling enteric bacterial diseases.

Nutritional management of gut health in pigs around weaning

Early weaning of piglets is often accompanied by a severe growth check and diarrhoea. It is well established that this process is multi-factorial and that post-weaning anorexia and undernutrition are major aetiological factors. Gastrointestinal disturbances include alterations in small intestine architecture and enzyme activities. Recent data indicate transiently-increased mucosal permeability, disturbed absorptive-secretory electrolyte balance and altered local inflammatory cytokine patterns after weaning. These responses appear to operate according to two distinct temporal patterns, an acute response followed by a long-lasting adaptation response. Pigs coexist with a diverse and dense commensal microbiota in their gastrointestinal tract. Most of these microbes are beneficial, providing necessary nutrients or protection against harmful pathogens for the host. The microbial colonisation of the porcine intestine begins at birth and follows a rapid succession during the neonatal and weaning period. Following the withdrawal of sow's milk the young piglets are highly susceptible to enteric diseases partly as a result of the altered balance between developing beneficial microbiota and the establishment of intestinal bacterial pathogens. The intestinal immune system of the newborn piglet is poorly developed at birth and undergoes a rapid period of expansion and specialisation that is not achieved before early (commercial) weaning. Here, new insights on the interactions between feed components, the commensal microbiota and the physiology and immunology of the host gastrointestinal tract are highlighted, and some novel dietary strategies are outlined that are focused on improving gut health. Prebiotics and probiotics are clear nutritional options, while convincing evidence is still lacking for other bioactive substances of vegetable origin.

Identification, characterization, epitope mapping, and three-dimensional modeling of the alpha-subunit of beta-conglycinin of soybean, a potential allergen for young pigs

Soybean meal (SBM), the major byproduct of soybean oil extraction, is the main protein source for swine diets globally. In the United States, 8.6 million metric tons of SBM was used in swine rations in 2004. The pathological effect and immunological response of SBM feeding have been demonstrated in swine. In this study, we have utilized plasma collected from piglet feed with SBM in immunoblot analysis to detect proteins that elicited antigenic responses. We have identified soybean beta-conglycinin alpha-subunit as being a potential allergen for young piglets. Characterization of this protein indicated that deglycosylation and pepsin digestion did not eliminate immunoreactivity of this protein. Epitope mapping utilizing planar cellulose supports technology (SPOT) showed that three peptides spanning amino acids S185-R231 were critical for the allergenicity. A computer-generated three-dimensional structure model of the alpha-subunit of beta-conglycinin indicated that the antigenic epitopes were located on the surface of the protein. Information from this study may assist in the construction of recombinant nonallergenic soybean protein useable for both immunotherapy and the potential production of hypoallergenic soybean plants.

Contribution of additives Cu to its accumulation in pig feces: study in Beijing and Fuxin of China

Massive amounts of pig manure are produced by intensive pig farm in China, and the composition of pig manure has changed much due to the use of feed additives. However, little is known about the exact Cu (copper) feed as additives or present as contaminants in pig feed and the residues in feces. One hundred and thirty-seven feeds and one hundred and forty-two fecal samples from 48 pig farms were collected in Beijing and Fuxin cities in 1999 and 2005, respectively. The concentrations of Cu were in the range of 6.86-395.19 mg/kg in the feed samples, and the mean values were in the order of weaner > grower-finisher > sow's feeds. The high concentrations over EU recommendations implied that excessive levels of Cu are fed on many pig farms in Beijing and Fuxin. Cu was also present in high concentrations in feces, and concentrations were highly variable. Cu concentrations in the feces from grower-finisher and weaner pigs were significantly greater than feces of sows. The super-intensive and small-scale farms had higher levels of Cu in feces than the middle farms. Cu concentrations in pig feces were approximately 5-times greater than in pig feeds. Feed management in grower-finisher pigs on super-intensive and small-scale pig farms is needed to reduce high Cu concentrations in feces and risks to soil contamination while feces are land-applied.

Antigenic specificity of serum antibodies in mice fed soy protein

BACKGROUND

Soybean protein is used in a number of food products but unfortunately is also a common cause of food allergy. Upon ingestion of soy protein, healthy mice like other animals and humans generate a soy-specific antibody response in the absence of signs of illness. Not much is known about the relationship between the immunogenic proteins involved in this nondeleterious antibody response and the pathological response associated with food allergy. The objective of the present study was to characterize the antigenic specificity of the soy protein-specific antibody response generated in healthy mice ingesting soy protein.

METHODS

Blood from mice fed a soy-containing diet was analyzed using ELISA and immunoblot for antibody reactivity towards various soy protein fractions and pure soy proteins/subunits. Mice bred on a soy-free diet were used as controls.

RESULTS

The detectable antigenic specificity of the serum antibodies of soy-consuming mice comprised glycinin and beta-conglycinin. Immunoblots with soy protein extract demonstrated antibody reactivity towards both the basic and the acidic chains of glycinin and the beta-conglycinin subunits with an individual response pattern among mice. Moreover, antibody reactivity was found towards the native quaternary structure of glycinin.

CONCLUSIONS

Mice ingesting soy protein generate an antibody response with reactivity towards glycinin and beta-conglycinin. Antibody reactivity found towards the native quaternary structure of glycinin indicates an oral immunogenicity of the highly processing-resistant oligomerized glycinin.