Application of resistant starch in swine and poultry diets with particular reference to gut health and function

Formic acid as an antibiotic alternative in broiler diets: effects on growth, carcass characteristics, blood chemistry, and intestinal microbial load

This study explored the ability of formic acid (FA) to replace antibiotics in broiler chicken diets. It examined how FA affected the chickens' growth, carcass characteristics, blood chemistry, and gut bacteria. The experiment randomly assigned 300 one-day-old (Ross 308) broiler chicks to 5 groups, each divided into 6 replicates with 10 unsexed chicks. The following were the treatments: 1st group, negative control (NC): only received a basal diet; 2nd group, positive control (PC): received a basal diet supplemented with 0.5 grams of Colistin antibiotic per kilogram of diet; 3rd, 4th, and 5th groups (FA2, FA4, and FA6) these groups received a basal diet along with formic acid added at increasing levels: 2, 4, and 6 Cm3 per kilogram of diet, respectively. Results found no significant differences in live body weight (LBW) or body weight gain (BWG) between treatment groups, except for LBW at one week and BWG at 0 to 1 and 4 to 5 wk of age. No significant variations were found in feed intake (FI) and feed conversion ratio (FCR) among the treatment groups, excluding FI and FCR at 1 to 2 wk of age. The treatments significantly impacted carcass traits, dressing percentage, breast meat, thigh meat, spleen, giblets, blood levels of urea, creatinine, total protein, globulin, and albumin, as well as the activity of enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in chicks fed different diets compared to control groups. The addition of FA to the diet significantly impacted antioxidant levels. Also, the FA2 group had the highest total bacterial count (TBC). However, the FA6 group was the opposite; it had the lowest levels of harmful bacteria, such as E. coli and Coliform. Supplementing broiler diets with formic acid improves blood parameters, antioxidant activity, and gut bacteria counts, with 4.0 cm³ formic acid/kg diet supplementation promoting optimal broiler health and product quality.

The influence of dietary supplementation with fermented agro-industrial residue of faba bean on Japanese quail performance, immunity, gut microbiota, blood chemistry, and antioxidant status

Antibiotic overuse in poultry feeds has disastrous implications; consequently, long-term alternatives must be developed. As a result, the current study aims to assess the impact of Aspergillus niger filtrate (ANF) high in organic acids grown on agro-industrial residue of faba bean (AIRFB) on quail diet, as well as their influence on bird productivity, digestion, carcass yield, blood chemistry, and intestinal microbiota. A total of 240 Japanese quails (aged 7 d) were used in this study, divided equally among 5 experimental groups with 48 quails each. Group 1 (G1) received a basal diet without any ANF, group 2 (G2) received a basal diet supplemented with 0.5 mL ANF/kg diet, group 3 (G3) received a basal diet supplemented with 1.0 mL ANF/kg diet, group 4 (G4) received a basal diet supplemented with 1.5 mL ANF/kg diet, and group 5 (G5) received a basal diet supplemented with 2 mL ANF/kg diet. The performance parameters were monitored at 1 to 3, 3 to 5, and 1 to 5 wk. Adding ANF increased body weight at 3 and 5 wk, as well as body weight gain at 1 to 3, 3 to 5, and 1 to 5 wk, compared to the control diet. The ANF fed quails had the highest feed conversion ratio compared to the control group. The addition of ANF to the quail diet had no effect on the weight of the carcass, gizzard, heart, liver, giblets, or dressing; however, it did lower triglycerides, low-density lipoprotein, and very low-density lipoprotein while increasing high-density lipoprotein levels. The quail groups that received ANF had enhanced immunological indices such as IgG, IgM, IgA, and lysozymes. It also increased the levels of superoxide dismutase and total antioxidant contents, as well as catalase, and digestive enzymes such as protease, amylase, and lipase. However, it lowered the blood MDA levels compared to control. It has been demonstrated that the total gut microbiota, Escherichia coli, total coliforms, and the population of Salmonella are all reduced in ANF-fed quails. Histological examination of ANF quails' liver and intestinal sections revealed normal hepatic parenchyma, typical leaf-like intestinal villi, and comparatively short and frequently free lumina. In conclusion, Japanese quail showed improvements in performance, digestive enzymes, antioxidant indices, immunity, and capacity to reduce intestinal pathogenic bacteria after consuming diet supplemented with ANF.

Dietary jack bean (Canavalia ensiformis L.) supplementation enhanced intestinal health by modulating intestinal integrity and immune responses of broiler chickens

This study investigated the influence of supplementing with jack beans on jejunal morphology, cecal short-chain fatty acids production, gene expression both of pro- and anti-inflammatory cytokines and tight junctions. Four treatment groups including 288 Indian River chicks that were one day old were randomized at random. While the treatment groups received jack bean supplementation at levels of 5 %, 10 %, and 15 %, the control group (0 %) was given a basal diet. For 11-35 days, each treatment consisted of 8 pens with 9 birds each. Supplementing with jack beans significantly enhanced butyrate production (P < 0.001), while at 10 % supplementation did not differ from control. Villus height (VH) and the ratio (VH:CD) were significantly (P < 0.001) increased by dietary treatments, while villus width (VW) and crypt depth (CD) were significantly (P < 0.05) decreased. TLR-3, TNF-a, and IL-6 were all significantly (P < 0.001) increased by dietary supplementation. However, at 15 %, TLR-3 and IL-6 were same with control. IL-18 was significantly (P < 0.05) decreased at 15 %. IL-10 decreased significantly (P < 0.001), but at 10 % same with control. At 5 and 10 %, IL-13 increased significantly (P < 0.001), whereas dietary treatments decreased at 15 % compared to control. Although ZO1 decreased significantly (P < 0.001) and OLCN increased significantly (P < 0.001), both ZO1 and OCLN were not significantly different from the control at 15 %. Dietary treatments significantly (P < 0.001) increased CLDN1 but did not differ from the control at 10 %. JAM2 decreased significantly (P < 0.001) with dietary treatments. In conclusion, jack bean supplementation may increase broiler chicken performance and intestinal health due to butyrate production. It may affect intestinal morphology and integrity by upregulating a tight junction protein gene. Jack beans also impacted jejunum immune responses and inflammatory cytokine gene expression.

The action of endo-xylanase and endo-glucanase on cereal cell wall polysaccharides and its implications for starch digestion kinetics in an in vitro poultry model

Endo-xylanase and endo-glucanase are supplemented to poultry diets in order to improve nutrient digestion and non-starch polysaccharide (NSP) fermentation. Here, the action of these enzymes on alcohol insoluble solids (AIS) from wheat and maize grains as well as its implications for starch digestion in milled grains were evaluated in vitro, under conditions mimicking the poultry digestive tract. For wheat AIS, GH11 endo-xylanase depolymerized soluble arabinoxylan (AX) during the gizzard phase, and proceeded to release insoluble AX under small intestine conditions. At the end of the in vitro digestion (480 min), the endo-xylanase, combined with a GH7 endo-β-1,4-glucanase, released 30.5 % of total AX and 18.1 % of total glucan in the form of arabinoxylo- and gluco-oligosaccharides, as detected by HPAEC-PAD and MALDI-TOF-MS. For maize AIS, the combined enzyme action released 2.2 % and 7.0 % of total AX and glucan, respectively. Analogous in vitro digestion experiments of whole grains demonstrated that the enzymatic release of oligomers coincided with altered grain microstructure, as examined by SEM. In the present study, cell wall hydrolysis did not affect in vitro starch digestion kinetics for cereal grains. This study contributes to understanding the action of feed enzymes on cereal NSP under conditions mimicking the poultry digestive tract.

Necrotic enteritis and antibiotic-free production of broiler chickens: Challenges in testing and using alternative products

The global trend towards raising broiler chickens without the use of in-feed antibiotics (IFAs) means that there is an ongoing need to develop alternative treatments capable of delivering the benefits that IFAs previously provided. IFAs supported the productivity performance of chickens and played a key role in maintaining their health. Necrotic enteritis (NE) is an important disease of broilers that affects health, productivity, and welfare, and was previously well controlled by IFAs. However, with the reduction in IFA use, NE is resurgent in some countries. Vaccines and various feed additives, including pre-, pro-, and postbiotics, phytobiotics, fatty acids, and phage therapies have been introduced as alternative methods of NE control. While some of these feed additives have specific activity against the NE pathogen, Clostridium perfringens, most have the more general goal of reinforcing gut health. Extensive reviews of the effects of many of these feed additives on gut health have been published recently. Hence, rather than cover previously well reviewed areas of research this review focuses on the challenges and pitfalls in undertaking experimental assessment of alternative NE treatments and translating laboratory research to real world commercial production settings. The review is based on the author's particular experience, reading, thoughts, and analysis of the available information and inevitably presents a particular understanding that is likely to be at odds with others thinking on these issues. It is put forward to stimulate thinking and discussion on the issues covered.

Effect of different heat-moisture treatment times on the structure, physicochemical properties and in vitro digestibility of japonica starch

Modified starch was prepared from japonica starch (JS) by heat-moisture treatments (HMT). Under the same moisture content and HMT temperature, the effects of various HMT times on the structural, properties of JS and its in vitro digestibility properties were investigated. The results showed that adhesion occurred between the particles of japonica starch after the HMT, and there were depressions on the surface. The size of the JS particles increased, the short-range ordering and relative crystallinity of the HMT-modified starch increased and gradually decreased, reaching a peak of 36.51 % at 6 h, as the HMT time was extended. The pasting indexes of HMT-modified starch decreased and then increased with the increase of the HMT time; compared with JS, the thermal stability of HMT-modified starch increased while the pasting enthalpy decreased. All the HMT-modified starches were weakly gelatinous systems and pseudoplastic fluids. Following HMT, the amount of resistant starch (RS) and slowly digested starch (SDS) grew initially before declining. The amount of RS in HMT-modified starch peaked at 24.28 % when the HMT time was 6 h. The results of this research can serve as a theoretical foundation for the creation of modified japonica starch and its use in the food industry.

The Effect of Prebiotic Supplements on the Gastrointestinal Microbiota and Associated Health Parameters in Pigs

Establishing a balanced and diverse microbiota in the GIT of pigs is crucial for optimizing health and performance throughout the production cycle. The post-weaning period is a critical phase, as it is often associated with dysbiosis, intestinal dysfunction and poor performance. Traditionally, intestinal dysfunctions associated with weaning have been alleviated using antibiotics and/or antimicrobials. However, increasing concerns regarding the prevalence of antimicrobial-resistant bacteria has prompted an industry-wide drive towards identifying natural sustainable dietary alternatives. Modulating the microbiota through dietary intervention can improve animal health by increasing the production of health-promoting metabolites associated with the improved microbiota, while limiting the establishment and proliferation of pathogenic bacteria. Prebiotics are a class of bioactive compounds that resist digestion by gastrointestinal enzymes, but which can still be utilized by beneficial microbes within the GIT. Prebiotics are a substrate for these beneficial microbes and therefore enhance their proliferation and abundance, leading to the increased production of health-promoting metabolites and suppression of pathogenic proliferation in the GIT. There are a vast range of prebiotics, including carbohydrates such as non-digestible oligosaccharides, beta-glucans, resistant starch, and inulin. Furthermore, the definition of a prebiotic has recently expanded to include novel prebiotics such as peptides and amino acids. A novel class of -biotics, referred to as "stimbiotics", was recently suggested. This bioactive group has microbiota-modulating capabilities and promotes increases in short-chain fatty acid (SCFA) production in a disproportionally greater manner than if they were merely substrates for bacterial fermentation. The aim of this review is to characterize the different prebiotics, detail the current understating of stimbiotics, and outline how supplementation to pigs at different stages of development and production can potentially modulate the GIT microbiota and subsequently improve the health and performance of animals.

Effects of dietary inclusion of dry distillers grains with solubles on performance, carcass characteristics, and nitrogen metabolism in meat sheep: a meta-analysis

We conducted a meta-analysis in this scientific study to determine the effects of feeding meat sheep dry distillers grains with solubles (DDGS). Thirty-three peer-reviewed articles that met our inclusion requirements and were published between 1997 and 2021 were examined. To calculate the variation in performance, fermentation, carcass features, and nitrogen efficiency between the DDGS and control (no DDGS) treatments, we used 940 sheep weighing an average of 29.1 ± 1.5 kg. We used a hierarchical mixed model to conduct a meta-regression, subset, and dose-response analysis, while taking into consideration categorical variables like breed (pure or cross-breed), and continuous factors, like CP, NDF, and DDGS inclusion rate. Our findings indicate that sheep fed DDGS had higher (p < 0.05) final body weight (51.4 vs. 50.4 kg), neutral detergent fiber digestibility (55.9 vs. 53.8%), and total-tract ether extract digestibility (81.7 vs. 78.7%) than sheep on a control diet. No effects were observed on DMI, CP, and rumen fermentation, but dietary DDGS tended to increase (p = 0.07) HC weight (25.53 vs. 24.6 kg) and meat (redness) color (16.6 vs. 16.3) among treatment comparisons. Dietary DDGS was associated with higher N intake (29.9 vs. 26.8 g/d), fecal N (8.2 vs. 7.8 g/d), and digestibility (71.9 vs. 68.5%). Urinary nitrogen was significantly (p < 0.05) affected linearly by increasing the intake of DDGS in the diet. Based on the dose-response analysis, dietary DDGS inclusion should not exceed 20% to avoid negative effects on performance, nitrogen metabolism, and meat color. Dietary protein from DDGS should not exceed 17% to prevent reduced TVFA concentrations. Breed strongly influenced (p < 0.05) RMD in performance, and inconsistent responses were observed between crossbreed and purebred sheep comparisons. Despite these inconsistencies, no publication bias was observed, but a high variance (Ω²) among comparisons-between-studies was detected. This meta-analysis showed evidence in support of the hypothesis that feeding meat sheep DDGS at a rate of 20% can improve their performance, digestibility, carcass weight, and meat color.

Overexpression of the ZmSUS1 gene alters the content and composition of endosperm starch in maize (Zea mays L.)

ZmSUS1 increases the amylose content of maize by regulating the expression of Shrunken2 (Sh2) and Brittle2 (Bt2) which encode the size subunits of endosperm ADP-glucose pyrophosphorylase, and Granule bound starchsynthase1 (GBSS1) and Starch synthase1 (SS1). Cereal crops accumulate starch in seeds as an energy reserve. Sucrose Synthase (SuSy) plays an important role in grain starch synthesis. In this study, ZmSUS1 was transformed into maize inbred line KN5585, and transgenic plants were obtained. Compared with the non-transgenic negative control, the content and activity of SuSy were significantly increased, the amylose content in mature seeds of transgenic maize increased by 41.1-69.2%, the total starch content increased by 5.0-13.5%, the 100-grain weight increased by 19.0-26.2% and the average diameter of starch granules increased by 10.8-17.2%. These results indicated that overexpression of ZmSUS1 can significantly improve the traits of maize seeds and obtain new lines with high amylose content. It was also found that the overexpression of ZmSUS1 may increase the amylose content by altering the expression of endosperm ADP-glucose pyrophosphorylase (AGPase) subunits Shrunken2 (Sh2) and Brittle2 (Bt2). Moreover, the ectopic expression of ZmSUS1 also affected the expression of Granule bound starch synthase1 (GBSS1) and Starch synthase1 (SS1) which encode starch synthase. This study proved the important role of ZmSUS1 in maize starch synthesis and provided a new technology strategy for improving maize starch content and yield.

Modified dietary fiber from cassava pulp affects the cecal microbial population, short-chain fatty acid, and ammonia production in broiler chickens

The objective of this study was to investigate the effects of modified dietary fiber from cassava pulp (M-DFCP) supplementation in broiler diets on cecal microbial populations, short-chain fatty acids (SCFAs), ammonia production, and immune responses. A total of 336, one-day-old male broiler chicks (Ross 308) were distributed over 4 dietary treatments in 7 replicate pens (n = 12 chicks) using a completely randomized design. Chicks were fed the control diet and 3 levels of M-DFCP (0.5, 1.0, and 1.5%) for an experimental duration of 42 d. The M-DFCP contained total dietary fiber (TDF), soluble dietary fiber (SDF), insoluble dietary fiber (IDF), cello-oligosaccharides (COS), and xylo-oligosaccharides (XOS) of approximately 280.70, 22.20, 258.50, 23.93, and 157.55 g/kg, respectively. The 1.0 and 1.5% M-DFCP supplementation diets showed positive effects on stimulating the growth of Lactobacillus spp. and Bifidobacterium spp., enhancing SCFAs (acetic, propionic, butyric acid, and branched SCFAs) and lactic acid concentrations during growing periods. Broilers fed 1.0 and 1.5% M-DFCP also exhibited a significant increase in caecal Lactobacillus spp. and lactic acid concentrations during the finisher period as well. In addition, M-DFCP also reduced cecal digesta and excreta ammonia production in broilers over both periods (0-21 and 22-42 d of age). However, M-DFCP did not exhibit any effect on total serum immunoglobulin (Ig) or lysozyme activity. In conclusion, this study shows that M-DFCP can be used as a dietary fiber source in broiler diets, with a recommended level of approximately 1.0%.

Using the dominant mutation gene Ae1-5180 (amylose extender) to develop high-amylose maize

Maize amylose is a type of high value-added starch used for medical, food, and chemical applications. Mutations in the starch branching enzyme (SBEIIb), with recessive ae (amylose extender) and dominant Ae1-5180 alleles, are the primary way to improve maize endosperm amylose content (AC). However, studies on Ae1-5180 mutation are scarce, and its roles in starch synthesis and breeding potential are unclear. We found that the AC of the Ae1-5180 mutant was 47.23%, and its kernels were tarnished and glassy and are easily distinguished from those of the wild type (WT), indicating that the dominant mutant has the classical characteristics of the ae mutant. Starch granules of Ae1-5180 became smaller, and higher in amount with irregular shape. The degree of amylopectin polymerisation changed to induce an increase in starch thermal stability. Compared with WT, the activity of granule-bound starch synthase and starch synthase was higher in early stages and lower in later stages, and other starch synthesis enzymes decreased during kernel development in the Ae1-5180 mutant. We successfully developed a marker (mu406) for the assisted selection of 17 Ae1-5180 near isogenic lines (NILs) according to the position of insertion of the Mu1 transposon in the SBEIIb promoter of Ae1-5180. JH214/Ae1-5180, CANS-1/Ae1-5180, CA240/Ae1-5180, and Z1698/Ae1-5180 have high breeding application potential with their higher AC (> 40%) and their 100-kernel weight decreased to < 25% compared to respective recurrent parents. Therefore, using the dominant Ae1-5180 mutant as a donor can detect the kernel phenotype and AC of Ae1-5180-NILs in advance, thereby accelerating the high-amylose breeding process.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11032-022-01323-7.

Review on Preventive Measures to Reduce Post-Weaning Diarrhoea in Piglets

In many countries, medical levels of zinc (typically as zinc oxide) are added to piglet diets in the first two weeks post-weaning to prevent the development of post-weaning diarrhoea (PWD). However, high levels of zinc constitute an environmental polluting agent, and may contribute to the development and/or maintenance of antimicrobial resistance (AMR) among bacteria. Consequently, the EU banned administering medical levels of zinc in pig diets as of June 2022. However, this may result in an increased use of antibiotic therapeutics to combat PWD and thereby an increased risk of further AMR development. The search for alternative measures against PWD with a minimum use of antibiotics and in the absence of medical levels of zinc has therefore been intensified over recent years, and feed-related measures, including feed ingredients, feed additives, and feeding strategies, are being intensively investigated. Furthermore, management strategies have been developed and are undoubtedly relevant; however, these will not be addressed in this review. Here, feed measures (and vaccines) are addressed, these being probiotics, prebiotics, synbiotics, postbiotics, proteobiotics, plants and plant extracts (in particular essential oils and tannins), macroalgae (particularly macroalgae-derived polysaccharides), dietary fibre, antimicrobial peptides, specific amino acids, dietary fatty acids, milk replacers, milk components, creep feed, vaccines, bacteriophages, and single-domain antibodies (nanobodies). The list covers measures with a rather long history and others that require significant development before their eventual use can be extended. To assess the potential of feed-related measures in combating PWD, the literature reviewed here has focused on studies reporting parameters of PWD (i.e., faeces score and/or faeces dry matter content during the first two weeks post-weaning). Although the impact on PWD (or related parameters) of the investigated measures may often be inconsistent, many studies do report positive effects. However, several studies have shown that control pigs do not suffer from diarrhoea, making it difficult to evaluate the biological and practical relevance of these improvements. From the reviewed literature, it is not possible to rank the efficacy of the various measures, and the efficacy most probably depends on a range of factors related to animal genetics and health status, additive doses used, composition of the feed, etc. We conclude that a combination of various measures is probably most recommendable in most situations. However, in this respect, it should be considered that combining strategies may lead to additive (e.g., synbiotics), synergistic (e.g., plant materials), or antagonistic (e.g., algae compounds) effects, requiring detailed knowledge on the modes of action in order to design effective strategies.

Antibiotic-induced alternations in gut microflora are associated with the suppression of immune-related pathways in grass carp (Ctenopharyngodon idellus)

Gut microbiota play a vital role in fish health homeostasis. Antibiotics are known to alter microbial community composition and diversity; however, the substantial effects of antibiotics upon the gut microbiome with respect to immune-related pathways in healthy fish remain unclear. Accordingly, here we explored the impact of two antibiotics on the intestinal health, immune response, microbiome dynamics, and transcriptome profiles of grass carp. A two-week feeding trial was carried out in which the basal diet was complemented with enrofloxacin (10 mg/kg) or florfenicol (10 mg/kg). The results showed that: (1) Enrofloxacin and florfenicol both induced intestinal oxidative stress and reduced the digestive enzyme activity of grass carp. (2) High-throughput sequencing of 16S rDNA revealed that enrofloxacin but not the florfenicol treatment influenced gut microbiota diversity in grass carp by shifting α/β-diversity with more abundant pathogens detected. (3) Transcriptome profiling demonstrated that florfenicol down-regulated the immune-related pathways of grass carp, and the network analysis revealed that IgA was negatively correlated with certain pathogens, such as Shewanella and Aeromonas. (4) Antibiotic-induced alternations of gut core microbes were revealed via immune-related transcripts, as were lower mRNA expression levels of mucosal-related genes. (5) Apoptosis and histopathological changes were detected in the enrofloxacin- and florfenicol-treated groups compared with the control group. Overall, administering antibiotics will promote oxidative stress, cause intestinal flora dysbiosis, inhibit the mucosal immune system, and induce apoptosis in grass carp.

Prebiotics and β-Glucan as gut modifier feed additives in modulation of growth performance, protein utilization status and dry matter and lactose digestibility in weanling pigs

There are growing interests in developing novel gut modifier feed additives and alternative therapeutics to replace antimicrobials to enhance efficiency of nutrient utilization and to address the antimicrobial resistance threat to public health facing the global pork production. Biological mechanisms of supplementing lactose for enhancing weanling pig growth and nitrogen utilization are unclear. Thus, this study was prompted to determine effects of dietary supplementation of 3 prebiotics and oat β-glucan vs. a sub-therapeutic antibiotic on growth performance, whole-body protein utilization status, the apparent total tract dry matter (DM) and lactose digestibility in weanling pigs fed corn and soybean meal (SBM)-based diets. Six experimental diets were formulated with corn (40%), SBM (28%) and supplemented with dried whey powder (20%) and fish meal (9%) with titanium oxide (0.30%) as the digestibility marker. Diet 1 (NC, negative control), as the basal diet, contained no antibiotics and no supplemental prebiotics or β-glucan. Diet 2 (PC, positive control), contained an antibiotic premix (Lincomix-44 at 0.10%) in the basal diet at the expense of cornstarch. Diets 3, 5 and 6 contained 0.75% of the three test prebiotics of retrograded cornstarch (Diet 3), Fibersol-2 (Diet 5, a modified digestion-resistant maltodextrin) and inulin (Diet 6), and the viscous soluble fiber oat β-glucan (Diet 4), respectively, at the expense of cornstarch. A total of 144 Yorkshire pigs, at the age of 21 days (d) and an average body weight (BW) of 5.5 kg, were allocated to 12 floor pens with 3 barrows and 3 gilts per pen, and fed one of the 6 diets for 21 d in 2 study blocks according to a completely randomized block design. Initial and final pig BW, average daily gain (ADG), average daily feed intake (ADFI), representative pig plasma urea concentration as well as the apparent total tract DM and lactose digestibility during d 8-15 were measured. Analyses of variances, Dunnett’s and Tukey’s tests were conducted on the endpoints by using the SAS mixed model. There were no differences (P &gt; 0.05) in ADG, ADFI, feed to gain ratio, plasma urea concentration, the apparent total tract apparent DM and lactose digestibility and the predicted whole-gut lactase digestive capacity among the diets, as examined by the Tukey’s test. There were no differences (P &gt; 0.05) in these endpoints between each of the four treatment diets and the NC or the PC diet as examined by the Dunnett’s test. The total tract lactose digestibility was determined to be at 100%. The predicted whole-gut lactase digestive capacity was about eight times of the daily lactose intake when dietary lactose contents were supplemented at 10 - 12% (as-fed basis). In conclusion, dietary supplementation (at 0.75%) of the prebiotics and the oat β-glucan did not significantly affect the major growth performance endpoints, whole-body protein utilization status as well as the apparent total tract DM and lactose digestibility in the weanling pigs fed the corn and SBM-based diets. The promoting effect for growth and nitrogen utilization associated with dietary supplementation of lactose is due to the fact that lactose is a completely and rapidly digestible sugar rather than acting as an effective prebiotic in weanling pig nutrition.

Invited review: strategic adoption of antibiotic-free pork production: the importance of a holistic approach

The discovery of the use of antibiotics to enhance growth in the 1950s proved to be one of the most dramatic and influential in the history of animal agriculture. Antibiotics have served animal agriculture, as well as human and animal medicine, well for more than seven decades, but emerging from this tremendous success has been the phenomenon of antimicrobial resistance. Consequently, human medicine and animal agriculture are being called upon, through legislation and/or marketplace demands, to reduce or eliminate antibiotics as growth promotants and even as therapeutics. As explained in this review, adoption of antibiotic-free (ABF) pork production would represent a sea change. By identifying key areas requiring attention, the clear message of this review is that success with ABF production, also referred to as "no antibiotics ever," demands a multifaceted and multidisciplinary approach. Too frequently, the topic has been approached in a piecemeal fashion by considering only one aspect of production, such as the use of certain feed additives or the adjustment in health management. Based on the literature and on practical experience, a more holistic approach is essential. It will require the modification of diet formulations to not only provide essential nutrients and energy, but to also maximize the effectiveness of normal immunological and physiological capabilities that support good health. It must also include the selection of effective non-antibiotic feed additives along with functional ingredients that have been shown to improve the utility and architecture of the gastrointestinal tract, to improve the microbiome, and to support the immune system. This holistic approach will require refining animal management strategies, including selection for more robust genetics, greater focus on care during the particularly sensitive perinatal and post-weaning periods, and practices that minimize social and environmental stressors. A clear strategy is needed to reduce pathogen load in the barn, such as greater emphasis on hygiene and biosecurity, adoption of a strategic vaccine program and the universal adoption of all-in-all-out housing. Of course, overall health management of the herd, as well as the details of animal flows, cannot be ignored. These management areas will support the basic biology of the pig in avoiding or, where necessary, overcoming pathogen challenges without the need for antibiotics, or at least with reduced usage.

Short Chain Fatty Acids and Bacterial Taxa Associated with Reduced Salmonella enterica serovar I 4,[5],12:i:- Shedding in Swine Fed a Diet Supplemented with Resistant Potato Starch

Salmonella enterica serovar I 4,[5],12:i:- is a foodborne pathogen of concern because many isolates are multidrug-resistant (resistant to ≥3 antimicrobial classes) and metal tolerant. In this study, three in-feed additives were individually tested for their ability to reduce Salmonella I 4,[5],12:i:- shedding in swine: resistant potato starch (RPS), high amylose corn starch, and a fatty acid blend, compared with a standard control diet over 21 days. Only RPS-fed pigs exhibited a reduction in Salmonella fecal shedding, different bacterial community compositions, and different cecal short chain fatty acid (SCFA) profiles relative to control animals. Within the RPS treatment group, pigs shedding the least Salmonella tended to have greater cecal concentrations of butyrate, valerate, caproate, and succinate. Additionally, among RPS-fed pigs, several bacterial taxa (Prevotella_7, Olsenella, and Bifidobacterium, and others) exhibited negative relationships between their abundances of and the amount of Salmonella in the feces of their hosts. Many of these same taxa also had significant positive associations with cecal concentrations of butyrate, valerate, caproate, even though they are not known to produce these SCFAs. Together, these data suggest the RPS-associated reduction in Salmonella shedding may be dependent on the establishment of bacterial cross feeding interactions that result in the production of certain SCFAs. However, directly feeding a fatty acid mix did not replicate the effect. RPS supplementation could be an effective means to reduce multidrug-resistant (MDR) S. enterica serovar I 4,[5],12:i:- in swine, provided appropriate bacterial communities are present in the gut. IMPORTANCE Prebiotics, such as resistant potato starch (RPS), are types of food that help to support beneficial bacteria and their activities in the intestines. Salmonella enterica serovar I 4,[5],12:i:- is a foodborne pathogen that commonly resides in the intestines of pigs without disease, but can make humans sick if unintentionally consumed. Here we show that in Salmonella inoculated pigs, feeding them a diet containing RPS altered the colonization and activity of certain beneficial bacteria in a way that reduced the amount of Salmonella in their feces. Additionally, within those fed RPS, swine with higher abundance of these types of beneficial bacteria had less Salmonella I 4,[5],12:i:- in their feces. This work illustrates likely synergy between the prebiotic RPS and the presence of certain gut microorganisms to reduce the amount of Salmonella in the feces of pigs and therefore reduce the risk that humans will become ill with MDR Salmonella serovar I 4,[5],12:i:-.

Role of Physiology, Immunity, Microbiota, and Infectious Diseases in the Gut Health of Poultry

“Gut health” refers to the physical state and physiological function of the gastrointestinal tract and in the livestock system; this topic is often focused on the complex interacting components of the intestinal system that influence animal growth performance and host-microbial homeostasis. Regardless, there is an increasing need to better understand the complexity of the intestinal system and the various factors that influence gut health, since the intestine is the largest immune and neuroendocrine organ that interacts with the most complex microbiome population. As we face the post-antibiotic growth promoters (AGP) era in many countries of the world, livestock need more options to deal with food security, food safety, and antibiotic resilience to maintain agricultural sustainability to feed the increasing human population. Furthermore, developing novel antibiotic alternative strategies needs a comprehensive understanding of how this complex system maintains homeostasis as we face unpredictable changes in external factors like antibiotic-resistant microbes, farming practices, climate changes, and consumers’ preferences for food. In this review, we attempt to assemble and summarize all the relevant information on chicken gut health to provide deeper insights into various aspects of gut health. Due to the broad and complex nature of the concept of “gut health”, we have highlighted the most pertinent factors related to the field performance of broiler chickens.

Resistant starch: Implications of dietary inclusion on gut health and growth in pigs: a review

Starch from cereal grains, pulse grains, and tubers is a major energy substrate in swine rations constituting up to 55% of the diet. In pigs, starch digestion is initiated by salivary and then pancreatic α-amylase, and has as final step the digestion of disaccharides by the brush-border enzymes in the small intestine that produce monosaccharides (glucose) for absorption. Resistant starch (RS) is the proportion of starch that escapes the enzymatic digestion and absorption in the small intestine. The undigested starch reaches the distal small intestine and hindgut for microbial fermentation, which produces short-chain fatty acids (SCFA) for absorption. SCFA in turn, influence microbial ecology and gut health of pigs. These fermentative metabolites exert their benefits on gut health through promoting growth and proliferation of enterocytes, maintenance of intestinal integrity and thus immunity, and modulation of the microbial community in part by suppressing the growth of pathogenic bacteria while selectively enhancing beneficial microbes. Thus, RS has the potential to confer prebiotic effects and may contribute to the improvement of intestinal health in pigs during the post-weaning period. Despite these benefits to the well-being of pigs, RS has a contradictory effect due to lower energetic efficiency of fermented vs. digested starch absorption products. The varying amount and type of RS interact differently with the digestion process along the gastrointestinal tract affecting its energy efficiency and host physiological responses including feed intake, energy metabolism, and feed efficiency. Results of research indicate that the use of RS as prebiotic may improve gut health and thereby, reduce the incidence of post-weaning diarrhea (PWD) and associated mortality. This review summarizes our current knowledge on the effects of RS on microbial ecology, gut health and growth performance in pigs.

Etiology of Colitis-Complex Diarrhea in Growing Pigs: A Review

Simple Summary

Diarrhea in growing pigs is a challenge for the pig industry since it is associated with reduced animal welfare, retarded growth, increased feed conversion ratio, and is often treated with antibiotics. One of the major causes of diarrhea in the growing period is large intestinal inflammation, often referred to as colitis. The exact causes of colitis-complex diarrhea are still to be understood, but dietary factors and/or pathogens have been recognized as the major factors in developing colitis-complex diarrhea. In this review, a thorough picture of pathogens, dietary factors, and a number of possible biomarkers related to colitis-complex diarrhea is presented.

Abstract

Colitis-complex diarrhea (CCD) in pigs can be defined as a type of diarrhea, which is associated with colonic inflammation and disrupted colonic gut barrier functionality in growing pigs (4–16 weeks post-weaning). It is a challenge for the pig industry as it is associated with the high use of antibiotics, reduced animal welfare, and depressed growth rate. The exact etiology of CCD is still unclear; however, pathogens including Brachyspira (B.) hyodysenteriae, B. pilosicoli, and swine whipworms such as Trichuris (T.) suis have been involved in specific colitis (SC). In the absence of specific pathogens, dietary factors, such as high levels of protein, pelleted feedstuffs, and lack of sufficient antioxidants, can result in non-specific colitis (NSC). On the other hand, supplement of polyunsaturated fatty acids (PUFA) and polyphenols, sufficient supply of essential amino acids (e.g., threonine, cysteine, and proline), short-chain fatty acids (SCFA; especially butyrate), and resistant starch have shown to confer preventing/ameliorating effects on CCD. Different putative biomarkers associated with CCD have been presented. It is anticipated that a comprehensive picture of the possible causes of CCD and potential dietary interventions could cast light on the direction of future studies aimed at developing preventive and curative strategies against CCD in growing pigs.

New Type of Food Processing Material: The Crystal Structure and Functional Properties of Waxy and Non-Waxy Proso Millet Resistant Starches

Resistant starch (RS) is widely used in the food industry because of its ability to regulate and protect the small intestine, but their distinct effects on the structural and functional properties of waxy and non-waxy proso millet starches are not completely understood. The crystalline structure and physicochemical properties of waxy and non-waxy proso millets' starch samples were analyzed after heat-moisture treatment (HMT). The analysis revealed significant differences between the RS of waxy and non-waxy proso millets. The crystal type of proso millets' starch changed from type A to type B + V. The relative crystallinity of the RS of waxy proso millet was better than that of non-waxy proso millet. The gelatinization temperature and thermal stability of RS significantly increased, and the pasting temperature (PTM) of the RS of waxy proso millet was the highest. The water solubility and swelling power of the RS in proso millet decreased, and the viscoelasticity improved. The correlation between the short-range ordered structure of RS and ΔH, and gelatinization properties has a stronger correlation. This study provides practical information for improving the nutritional benefits of waxy and non-waxy proso millet in food applications.

Total and resistant starch from foodstuff for animal and human consumption in Costa Rica

Starchy ingredients are a key source of carbohydrates and have an essential role in a healthy diet. Starch amount in foodstuffs is paramount as it allows diet professionals to base their formulations on scientific data. Herein, the total (TS) and resistant starch (RS) content, in a selection of typical starchy foods available on the Costa Rican market, for both human and animal consumption, is reported. The major types of starch, including physically encapsulated starch, were determined using in vitro methods AOAC OMASM methods 996.11, 2014.10, 996.11, 2002.02 and AACC 76-13.01 and 32-40.01. Samples were collected during 5 years as part of national surveillance plans. For feedstuffs, n = 252 feed ingredients (e.g., cornmeal and wheat products), n = 103 feeds (e.g., dairy and beef cattle), and n = 150 feed ingredient samples (selected based on their usage in feed formulations) were assessed for RS. In food commodities, sample numbers ascended to n = 287 and n = 371 for TS and RS, respectively (e.g. bananas). Feed ingredients with higher TS values were cassava meal, bakery by-products, rice/broken, sweet potato, and cornmeal (93.37, 81.67, 72.33, 66.66, and 61.43 g/100 g, respectively). TS for beef and dairy cattle, pig, and calf feeds, ranged from 30.26 to 34.46 g/100 g. Plantain/green banana flour, as a feed ingredient, exhibited RS absolute and relative contributions of 37.04 g/100 g and 53.89%, respectively. Products with a higher TS content included banana flour, green plantain flour, japonica rice, and cassava flour (62.87, 63.10, 72.90, 83.37 g/100 g). The primary RS sources in the Costa Rican diet are, in absolute terms, green plantain and malanga (50.41 and 56.59 g/100 g). Depending on a person's food habits, these sources may contribute in the range of 20-30 grams of RS per day. TS and RS intake may vary considerably among ingredients, and the contribution of RS may be of nutritional importance for specific individuals.

Effect of feeding 3 zero-tannin faba bean cultivars at 3 increasing inclusion levels on growth performance, carcass traits, and yield of saleable cuts of broiler chickens

A trial was conducted to evaluate how rapidly one could introduce faba bean in broiler diets and to what maximum level one could feed 3 zero-tannin faba bean cultivars to broiler chickens based on growth performance, carcass traits, and yield of carcass cuts. A total of 662 male broiler chickens (Ross 708) were fed one of 10 dietary treatments over 3 growth phases (starter [Str], day 0–12; grower [Gwr], day 13–25; and finisher [Fnr], day 26–41). Treatment diets included 3 different zero-tannin faba bean cultivars (Snowbird, Snowdrop, and Tabasco), each fed at 3 different inclusions: low inclusion level of 5% in Str, 10% in Gwr, and 20% in Fnr; medium inclusion level of 10% in Str, 20% in Gwr, and 30% in Fnr; and high inclusion level of 15% in Str, 30% in Gwr, and 40% in Fnr. Wheat grain–soybean meal (SBM) diets were fed as control. Faba bean cultivars replaced SBM and wheat grain in phase diets. Neither cultivar nor inclusion level affected overall trial or growth phase BW, ADFI, ADG, G:F, slaughter weight (WT), chilled carcass WT, and proportion of saleable cuts. Carcass dressing was 0.6% units lower for high vs. medium or low faba bean inclusion level (P < 0.05). There was no effect on overall trial or growth phase ADFI and there were only slight reductions (P < 0.05) in BW, ADG, G:F, slaughter WT, chilled carcass WT, dressing percentage, and percentage of drumstick yield in broilers fed the treatment diets including faba bean compared with those fed the wheat–SBM control diet. The control diet's advantage was largely attributed to dehulling and the greater extent of processing to produce SBM vs. feeding raw, merely rolled, faba bean. In conclusion, broiler producers can feed any of the 3 zero-tannin faba bean cultivars evaluated as the most aggressive of the 3 inclusion levels tested (15, 30, 40% for the starter, grower, finisher phase) to maximize faba bean inclusion in broiler diets.

Regulation of tartary buckwheat-resistant starch on intestinal microflora in mice fed with high-fat diet

Resistant starch (RS) is closely related to the composition of intestinal flora. Based on many studies on the physiological functions of probiotics and short-chain fatty acids (SCFAs), it is possible that RS can improve the intestinal health of the host. Therefore, we speculated that tartary buckwheat-resistant starch (TBRS) can also regulate the intestinal flora disorder caused by high-fat diet. We randomly divided 36 SPF C57BL/6J mice into low-fat diet, high-fat diet (HF-CS), high-fat diet supplemented with TBRS (HF-BRS), and high-fat diet supplemented with corn-resistant starch (HF-CRS). We analyzed the diversity and richness of gut microbiota based on PCR and Illumina high-throughput sequencing technology. In community abundance, the HF-BRS group was significantly higher than the other three groups (p < .05). TBRS improved the gut microbiota dysbiosis, including decreasing the Firmicutes-to-Bacteroidetes ratios (F/B) and contributing to the growth of Bacteroides and Blautia as well significantly inhibiting the growth of Bifidobacterium, Faecalibaculum, and Erysipelatoclostridium. We also analyzed the production of SCFAs by GC-MS, and the concentration of total SCFAs increased in the HF-CS group. However, TBRS significantly increased the production of SCFAs, especially the propionate concentration compared with the HF-CRS group (p < .05). These results elucidated that TBRS has the potential to improve intestinal health by altering the structure of gut microbiota and increasing the production of SCFAs. Our findings have important implications for TBRS as functional food ingredient to manipulate intestinal microflora.

Maternal dietary resistant starch does not improve piglet's gut and liver metabolism when challenged with a high fat diet

Background

In the past several years, the use of resistant starch (RS) as prebiotic has extensively been studied in pigs, and this mostly in the critical period around weaning. RS is believed to exert beneficial effects on the gastrointestinal tract mainly due to higher levels of short chain fatty acids (SCFAs) and an improved microbiota profile. In this study, sows were fed digestible starch (DS) or RS during late gestation and lactation and the possible maternal effect of RS on the overall health of the progeny was assessed. Since RS is also described to have a positive effect on metabolism, and to investigate a metabolic programming of the progeny, half of the piglets per maternal diet were assigned to a high fat diet from weaning on to 10 weeks after.

Results

No bodyweight differences were found between the four experimental piglet groups. The high fat diet did however impact back fat thickness and meat percentage whereas maternal diet did not influence these parameters. The impact of the high fat diet was also reflected in higher levels of serum cholesterol. No major differences in microbiota could be distinguished, although higher levels of SCFA were seen in the colon of piglets born from RS fed sows, and some differences in SCFA production were observed in the caecum, mainly due to piglet diet. RNA-sequencing on liver and colon scrapings revealed minor differences between the maternal diet groups. Merely a handful of genes was differentially expressed between piglets from DS and RS sows, and network analysis showed only one significant cluster of genes in the liver due to the maternal diet that did not point to meaningful biological pathways. However, the high fat diet resulted in liver gene clusters that were significantly correlated with piglet diet, of which one is annotated for lipid metabolic processes. These clusters were not correlated with maternal diet.

Conclusions

There is only a minor impact of maternal dietary RS on the progeny, reflected in SCFA changes. A high fat diet given to the progeny directly evokes metabolic changes in the liver, without any maternal programming by a RS diet.

Effect of lotus seed resistant starch on tolerance of mice fecal microbiota to bile salt

We investigated the effect of lotus seed resistant starch (LRS) on mice fecal microbiota tolerance to bile salt by culturing organisms compared to inulin (INU) glucose (GLU) and waxy corn starch (WAX). Operational taxonomic units (OTUs) and diversity indices in LRS and INU groups were increased in the presence of 0.03% to 0.3% bile salt, while they were decreased in GLU, and OTUs were decreased in WAX. Specifically, LRS promoted proliferation of Lactobacillus, which potentially used bile acid, and inhibited growth of the potentially harmful bacteria Enterococcus and Staphylococcus. Moreover, Lactobacillus was negatively correlated with Salinicoccus and Granulicatella in GLU, LRS and INU groups at 1.5% bile salt. With LRS, amino acid metabolic pathways were increased while pathogens causing certain diseases were decreased. LRS increased the tolerance of mice fecal microbiota to bile salt by promoting the proliferation of bacteria utilizing bile acid and inhibiting the growth of harmful bacteria.

The growth performance, intestinal digestive and absorptive capabilities in piglets with different lengths of small intestines

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties.

Growth performance, carcass traits and digestive function of broiler chickens fed diets with graded levels of corn resistant starch

1. This study was conducted to assess the effects of graded levels of dietary corn resistant starch (RS) on growth performance, carcass traits, nutrient retention, digestive organ index, intestinal morphology, digestive enzyme activities, and mRNA expression of certain nutrient transporters in broiler chickens.2. A total of 320, 1-d-old Arbor Acres broiler chickens were randomly assigned to five dietary treatments, with eight replicates of eight birds in each. These treatments included one corn-soybean control diet, a corn-soybean based diet containing 20% corn starch, and three diets supplemented with 4%, 8% and 12% RS by replacing corn starch with 6.67%, 13.33% and 20% of Hi-Maize 260® (identified as control, RS1, RS2, RS3 and RS4, respectively). The feeding period lasted 42 days.3. Performance parameters including feed consumption, feed conversion, body weight gain and percentage of abdominal fat at d 42 of age, nutrient retention (including dry matter, fat, total starch and nitrogen free extract), and apparent metabolisable energy was measured from d 18 to 20 and d 39 to 41 and showed negative linear responses to increasing dietary RS level (P < 0.05). Birds fed the RS3 and RS4 diets showed higher relative weight of duodenum, jejunum and ileum, as well as lower villus height and villus height/crypt depth compared to the control (P < 0.05). The activity of pancreatic trypsin of birds at d 21 and 42 of age decreased linearly in response to the increase of dietary RS level (P < 0.01). There were linear changes in up-regulated mRNA expression of SGLT-1 and down-regulated mRNA expression of GLUT-2 with increasing proportion of RS at d 21 and 42 of age (P < 0.05), respectively.4. It was concluded that feeding broilers with diets containing higher concentrations of RS impaired the development of small intestine, which resulted in lower apparent total tract retention of nutrients and poorer body weight gain, feed efficiency and carcass traits of broiler chickens.

The preparation, formation, fermentability, and applications of resistant starch

Resistant starch (RS) cannot be digested in the small intestine but can be fermented by microflora in the colon. To meet the demand for RS, effective methods and advanced equipment for preparing RS have emerged, but further development is needed. RS contents are affected by different prepared methods, starch source and certain nutrients such as protein, phenols, and hydrocolloids interacted with RS. As a beneficial fermentation substrate, RS modifies and stabilizes the intestinal flora to balance the intestinal environment and improve intestinal tract health and function. RS is also a kind of ingredient with potential physiological function, even better than that dietary fiber, but also in terms of providing various health benefits. RS has good food-processing characteristics as well and can thus be widely used in the food industry.

Time-Dependent Changes in the Intestinal Microbiome of Gilts Exposed to Low Zearalenone Doses

Zearalenone is a frequent contaminant of cereals and their by-products in regions with a temperate climate. This toxic molecule is produced naturally by Fusarium fungi in crops. The aim of this study was to determine the influence of low zearalenone doses (LOAEL, NOAEL and MABEL) on the intestinal microbiome of gilts on different days of exposure (days 7, 21 and 42). Intestinal contents were sampled from the duodenal cap, the third part of the duodenum, jejunum, caecum and the descending colon. The experiment was performed on 60 clinically healthy gilts with average BW of 14.5 ± 2 kg, divided into three experimental groups and a control group. Group ZEN5 animals were orally administered ZEN at 5 μg /kg BW, group ZEN10-10 μg ZEN/kg BW and group ZEN15-15 µg ZEN/kg BW. Five gilts from every group were euthanized on analytical dates 1, 2 and 3. Differences in the log values of microbial counts, mainly Escherichia coli and Enterococcus faecalis, were observed between the proximal and distal segments of the intestinal tract on different analytical dates as well as in the entire intestinal tract. Zearalenone affected the colony counts of intestinal microbiota rather than microbiome diversity, and its effect was greatest in groups ZEN10 and ZEN15. Microbial colony counts were similar in groups ZEN5 and C. In the analysed mycobiome, ZEN exerted a stimulatory effect on the log values of yeast and mould counts in all intestinal segments, in particular in the colon, and the greatest increase was noted on the first analytical date.

Changes in the intestine microbial, digestion and immunity of Litopenaeus vannamei in response to dietary resistant starch

Resistant starch (RS) is a constituent of dietary fibre that has beneficial effects on the intestine physiological function of animals. However, the roles of RS on shrimp intestine health is unknown. In this study, we investigated the the effects of dietary RS on the microbial composition, and digestive and immune-related indices in the intestine of Litopenaeus vannamei. The shrimp were fed with diets containing different levels of RS: 0 g/kg (Control), 10 g/kg (RS1), 30 g/kg (RS2) and 50 g/kg (RS3) for 56 days. The results showed that dietary RS improved the morphology of the intestine mucosa. RS also increased the activity of digestive enzymes (AMS, LPS, Tryp, and Pep) and immune enzymes (PO, T-AOC, T-NOS, and NO), and the expression levels of immune-related genes (proPO, ALF, Lys, HSP70, Trx, Muc-1, Muc-2, Muc-5AC, Muc-5B, and Muc-19). A microbiome analysis indicated that dietary RS increased the short-chain fatty acids (SCFAs) contents and altered the composition of the intestine microbial. Specifically, RS increased the abundances of Proteobacteria and decreased the abundance of Bacteroidetes. At the genus level, the beneficial bacteria (Lutimonas, Ruegeria, Shimia, Mesoflavibacter, and Mameliella) were enriched, which might be involved in degrading toxins and producing beneficial metabolites; while potential pathogens (Formosa and Pseudoalteromonas) were decreased in response to dietary RS. Our results revealed that dietary RS could improve the intestine health of L. vannamei, probably via modulating the intestine microbial composition and SCFAs contents, and enhancing the digestion and immunity of the shrimp.

Role of Feed Processing on Gut Health and Function in Pigs and Poultry: Conundrum of Optimal Particle Size and Hydrothermal Regimens

The aim is to give an overview of available literature data on the role of feed processing on gut health and function with specific focus on particle size and hydrothermal processing. In addition, influence of feed processing on efficacy of exogenous feed enzymes will be discussed. The current feed processing technologies are such that ingredient choices and diet form are refined to improve feed intake and nutrient utilization efficiency. Finer feed particle size enables optimal nutrient utilization and enhances animal performance due to increased surface area allowing better contact with digestive enzymes. Moreover, adequate diminution of feed ingredients is beneficial to feed manufacturing processes such as mixing and hydrothermal treatments including pelleting, extrusion, and expansion. However, emerging trends in consumer and regulatory demands for restriction or cessation of animal production practices such as use of antimicrobial growth promoters are challenging current approaches to feed processing. There is limit as to the fineness of the particle size, as very fine particles negatively affect gut health due to higher incidences of stomach ulceration in pigs and gizzard dysfunction in poultry. Coarse particle size increases stomach and hindgut acidification which may be beneficial in controlling proliferation of enteric pathogens such as salmonella and E. coli. Optimal particle size could be designed in the grinding process using roller or hammer mill. However, since most commercial pigs and poultry diets are subjected to hydrothermal processes, additional reduction of feed particle size is inevitable. The need to achieve high physical quality and to reduce potential levels of feed-borne pathogens such as Salmonella has led to the application of relatively high conditioning temperatures during conventional hydrothermal processes, a practice that does not favor high nutrient utilization and stability of heat sensitive feed additives such as feed enzymes. Therefore, with evolving pig and poultry production practices, the regimens for feed processing will no longer be appreciated only in terms of optimizing nutrients utilization, but also in terms of impact on feed hygienic status, efficacy of feed additives, animal health, and food safety.