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Curcumin (CUR) is a natural polyphenolic substance that has been widely used since ancient times for its multiple beneficial functions. However, whether CUR affects the growth performance of broilers by altering gut microbiota and metabolite and the underlying mechanism are largely unknown. This study was conducted to evaluate the effect of dietary CUR supplementation on growth performance, anti-inflammatory function, intestinal morphology and barrier, cecum microbiota, and metabolite profile of broilers. Sixty-one-day-old male broilers were randomly divided into the control group (CON, fed a control diet) and the CUR group (fed a control diet supplemented with 200 mg/kg CUR) after 2 d of adaptation. Results showed that after feeding to 52-d-old, compared with CON broilers, the CUR broilers showed improved feed utilization efficiency and growth performance. Furthermore, the CUR broilers showed an improved intestinal morphology, which was demonstrated by a lower crypt depth in the jejunum. The 16S rRNA gene sequencing and non-targeted metabonomics (LC-MS/MS) analysis results showed that the cecum microbiota ecology and function were significantly improved, and the abundance of beneficial flora and metabolites were increased, while the harmful bacteria and metabolites were significantly decreased. In addition, RT-qPCR results showed that CUR significantly reduced inflammatory responses, promoted the formation of the mucosal barrier and enhanced digestion, absorption, and transport of lipids and glucose-related gene expression in the intestine. These above findings demonstrated that dietary CUR supplementation improved growth performance, intestinal morphology, and anti-inflammatory functions, mainly by manipulating cecum microbiota and microbiota-derived metabolites, which provides a credible explanation for the growth-promoting effect and anti-inflammatory functions of CUR and aids our understanding of the mechanisms underlying., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Acetic acid, which is one of the most abundant short-chain fatty acids (SCFA) in rabbits' cecum, has been reported to play an important function during various physiological metabolic processes. The present study was conducted to elucidate the effects of sodium acetate on growth performance and intestinal health by evaluating feed intake and efficiency, diarrhea score, serum and cecum metabolites, cecal pH and SCFA, histological staining, nutritional composition of meat and gene expression profile of cecum in rabbits. As a result of sodium acetate supplement, the feed conversion ratio, diarrhea score, and diameter of muscle fiber were significantly decreased (P < 0.05). Additionally, dietary sodium acetate significantly increased in total area of muscle fibers and content of crude ash (P < 0.05). Dietary sodium acetate significantly increased serum glucose, total bile acid, and total cholesterol levels and decreased amylase, lipase, and tCO2 content (P < 0.05). Further examination suggested that sodium acetate supplementation enhanced the micro-environment of cecum, evidenced by significantly increased levels of total antioxidant capacity, total superoxide dismutase, and glutathione peroxidase, and decreased pH and amylase levels (P < 0.05). According to transcriptome sequencing of cecal tissues, differentially expressed genes were predominantly enriched in cell cycle, ABC transporters, and chemokine signaling pathways. Sodium acetate was further suggested to stimulate the proliferation and migration of rabbits' cecum epithelial cells by activating Wnt/β-catenin pathway both in vivo and in vitro. In conclusion, dietary sodium acetate supplementation improved growth performance and intestinal health in rabbits., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Plant essential oils are unstable due to high volatility and easy oxidation, while microencapsulation provides a potentially effective strategy for increasing the stability of natural essential oils and preserving their function. This study examined the effects of feeding coated oregano essential oil and cinnamaldehyde (COEC) compounds on growth, immune organ development, intestinal morphology, mucosal immune function, and the cecal microbiota populations of broilers. Three hundred one-day-old male Arbor Acres broiler chicks were organized into 5 groups: 1) negative control fed basal diet alone (NC), 2) positive control receiving basal diet plus 50 mg/kg of chlortetracycline (CTC), 3) basal diet plus 150 mg/kg COEC (COEC150), 4) plus 300 mg/kg COEC (COEC300), and 5) plus 450 mg/kg COEC (COEC450). The supplement trial was continued for 42 d. The results showed that CTC, COEC300, and COEC450 treatments decreased the feed conversion ratio of broilers both in the starter and whole experiment phases, increased the height of jejunal villi at 21 d and the number of goblet cells and IgA-producing cells at 21 or 42 d compared with NC group (P < 0.05). Members of the COEC300 treatment group had a higher thymus weight index and jejunum length index than birds of NC or CTC groups at 21 d (P < 0.05). CTC and all COEC treatments decreased malondialdehyde content in jejunal mucosa at 42 d (P < 0.05). The population of Escherichia coli (E. coli) in the cecal digesta at 21 d was lower in the CTC, COEC300, and COEC450 treatment groups compared with the NC group (P < 0.05). In contrast to the CTC group, COEC supplementation dose-dependently accelerated body weight gain, improved jejunal morphology, decreased malondialdehyde content in jejunal mucosa, increased numbers of jejunal goblet cells and IgA-producing cells, and decreased the E. coli population in cecal digesta at 21 or 42 d (P < 0.05). Thus, we concluded that feeding broiler chickens with 300 or 450 mg/kg in antibiotic-free diets can improve growth performance, enhance immune responses, and inhibit the proliferation of cecal pathogenic bacteria., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The present research aimed to evaluate the effects of the continuative dietary administration of a hemp oil extract containing cannabinoids (cannabidiol, CBD) on the macroscopic morphology, morphometry, and enzymatic activity of different intestinal tracts as well as on the production of short-chain fatty acids (SCFAs) in the cecum of growing rabbits. The research was performed on 16 rabbits randomly selected from 2 experimental groups (8 per group). In detail, 42 sixty-day-old New Zealand White × California rabbits (sex ratio 1:1, average weight 1621.3 ± 46.2 g) were homogeneously divided into 2 groups (21 animals/group), namely control and CBD. Both groups were fed the same commercial diet, but the CBD one was supplemented with 0.1 mL of hemp extract in coconut-based oil corresponding to 10 mg of CBD/animal/d. Up to 92 d of age (for 27 d), individual live weight and feed intake were measured weekly. At 92 d of age, 8 rabbits/group (sex ratio 1:1) were moved to a specialized slaughterhouse, and the gastrointestinal tract was separated from the carcass. Samples from 8 rabbits per dietary treatment were used for the histomorphological analysis of small and large intestines. In addition, duodenum, jejunum, ileum, and cecum were processed for enzymatic analysis. The caecal contents were used for the SCFAs determination. The administration of CBD did not affect feed intake and the final rabbits' whole body weight (P > 0.05), but some changes were detected in the gastrointestinal tract of the animals. CBD seemed to interfere with protein digestion, with a significantly lower activity of the enzymes related to peptides in the small intestine and a consequent increase of the fermentative activity of caecal microbiota. This effect, in combination with a general decrease of fermentative activity in the caecal content of rabbits submitted to CBD treatment, was responsible for a change in the SCFA proportion mainly regarding the reduction of butyrate production (P < 0.01) that resulted significant higher in CTR group compared to CBD. This last result is very important for intestinal health. Such fermentation activity modification was coupled with changes in the relative abundance of goblet cells in the colon. Overall, our findings suggest that a relatively long-term administration of CBD may affect digestion in rabbits, in particular at enzymatic and fermentative levels., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

A study was conducted to determine effects of reducing hindgut pH through dietary inclusion of high-amylose cornstarch (HA-starch) on growth performance, organ weights relative to live body weight (BW), blood thyroid hormone levels, and glucosinolate degradation products of nursery pigs fed cold-pressed canola cake (CPCC). A total of 240 pigs (initial BW: 7.1 kg), which had been weaned at 21 d of age, were housed in 40 pens (6 pigs per pen) and fed 4 diets (10 pens per diet) in a randomized complete block design for 28 d. Four diets were a basal diet with CPCC at 0 or 40%, and with HA-starch at 0 or 40% in a 2 × 2 factorial arrangement. The diets were fed in two phases: Phase 1 from day 0 to 14 and Phase 2 from day 14 to 28 and were formulated to have the same net energy, standardized ileal digestible AA, Ca, and standardized total tract digestible P contents. Dietary inclusion of CPCC and HA-starch was achieved by a partial or complete replacement of corn, soybean meal, and soy protein. At the end of the study, one pig from each pen was euthanized to determine organ weights, blood parameters, hindgut pH, and glucosinolate degradation products. Dietary CPCC reduced (P < 0.05) overall average daily gain (ADG) by 15%; increased (P < 0.05) relative weights of liver and thyroid gland by 27% and 64%, respectively; and reduced (P < 0.05) serum tetraiodothyronine (T4) level from 30.3 to 17.8 ng/mL. Heart, kidney, and gastrointestinal tract weights; serum triiodothyronine level; and hindgut pH of pigs were unaffected by dietary CPCC. Dietary HA-starch reduced (P < 0.05) overall ADG, relative weight of thyroid gland, cecal, and colonic pH; but increased (P < 0.05) relative weight of colon; tended to increase (P = 0.062) serum T4 level. Dietary CPCC and HA-starch interacted (P = 0.024) on relative weight of thyroid gland such that dietary CPCC increased (P < 0.05) weight of thyroid gland for HA-starch-free diet (120 vs. 197 mg/kg of BW) but not for HA-starch-containing diet (104 vs. 130 mg/kg of BW). Dietary CPCC and HA-starch interacted (P = 0.001) on cecal isothiocyanate content such that dietary CPCC increased (P < 0.05) level of isothiocyanates for HA-starch-containing diet but not for HA-starch-free diet. In conclusion, dietary CPCC reduced growth performance, increased liver, size and interfered with thyroid gland functions of pigs. However, the negative effects of dietary CPCC on thyroid gland functions of nursery pigs were alleviated by dietary HA-starch., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This study aimed to investigate the effect of dietary cysteamine hydrochloride (CSH) on the growth performance, oxidation, inflammation, and gene expression of cytoskeleton and tight junction in the intestinal mucosa of broiler chickens challenged with Clostridium perfringens (C. perfringens). A total of 360 one-day-old broiler chicks were randomly distributed into 5 groups for a negative control (NC, without C. perfringens challenge), a positive control (PC, with C. perfringens challenge), and PC plus CSH at 100, 150, or 200 mg/kg of diet. The results showed that average daily gain, gain:feed, cecal population and enterotoxin of C. perfringens were negatively affected (P < 0.05) by the C. perfringens challenge, but were conversely affected (P < 0.05) by the CSH supplementation, and G:F reached to the level of NC group. The PC group increased (P < 0.05) serum diamine oxidase, malondialdehyde, protein carbonyl, interleukin-6, interleukin-1β, and tumor necrosis factor-α, whereas the supplementation of CSH decreased (P < 0.05) these parameters. Moreover, the C. perfringens challenge worsened the disruption of intestinal mucosal cytoskeleton and tight junction by downregulating (P < 0.05) the mRNA levels of actin protein of muscle Z-line alpha, syncoilin, synemin, tubulin, claudin-1, and zona occludens protein-2, while these parameters were partially compensated (P < 0.05) by CSH supplementation. For the dose trends of CSH, there were linear and quadratic (P < 0.05) effects on gain:feed, enterotoxins, tumor necrosis factor-α, tubulin alpha 1c, syncoilin, and synemin. In conclusion, the CSH can be an alternative against C. perfringens infection by beneficially regulating gut pathogenic bacteria and enterotoxins, oxidation, inflammation, cytoskeleton, and tight junction in broiler chickens.

Two studies were conducted to evaluate the effects of organic acid (OA) supplementation in a highly digestible (Exp. 1) or a less digestible diet (Exp. 2) on the growth performance and intestinal health of weaned pigs. In Exp. 1, a total of 240 pigs weaned at day 21 were assigned to one of five dietary treatments: negative control (NC) (basal diet, 3,000 ppm zinc oxide (ZnO) in the first 2 wk only); positive control (PC) (NC plus 10 mg/kg zinc bacitracin, 5 mg/kg colistin sulfate, and 5 mg/kg olaquindox); OA1 (NC plus a 0.2% blend of encapsulated butyrate, medium-chain fatty acids [MCFA], OA, and phenolics); OA2 (NC plus 0.3% blend of free and buffered short-chain fatty acids [SCFA] combined with MCFA); and OA1 plus OA2 (NC plus 0.2% OA1 plus 0.3% OA2) for 49 d. All treatments in Exp. 1 used the same highly digestible basal diet. At day 28, eight pigs from each group were sacrificed, to collect intestinal and digesta samples for biochemical analysis. Growth performance and intestinal morphology were not affected by the treatments. However, pigs subjected to the OA2 treatment had lower levels of Escherichia coli (P < 0.05) in the colon. In addition, the OA1 and OA2 treatments, and their combination resulted in higher concentrations of acetate and propionic acid in the cecum and colon (P < 0.01) in comparison to the NC. A less digestible diet without high levels of ZnO was used in Exp. 2. A similar design was used with the exception of the replacement of OA2 with another OA blend (OA3, a blend of free and buffered OA). In comparison to the NC, supplementation with OA1 and OA3 in a less digestible diet improved the ADG and the F:G ratio in the seventh week post-weaning (P < 0.01); reduced the diarrhea index of pigs during the first 3 wk post-weaning (P < 0.05); increased the ileal villus height (P < 0.05), and acetic and propionic acid concentrations in colon contents (P < 0.05). Moreover, the genus Prevotella was increased in the colon and the microbial community structure was significantly altered in the OA1 + OA3 treatment. The present research indicated that dietary supplementation with OA improved intestinal health. The OA blends showed a similar growth-promoting effect as antibiotics in the less digestible diet, to which high levels of ZnO had not been added.

The objective of this study was to investigate the effect of dietary supplementation with fish oil on growth performance (during all fatening period), carcass characteristics and fatty acid (FA) profile of muscle and fat tissues (at slaughter), as well as cecal fermentation and ileal mucosa morphology of growing rabbits (at 30, 45, and 60 d of age). Two isonitrogenous and isoenergetic diets, only differing in their fat source, were formulated and provided each to 24 does (12 per diet) and their offspring during pregnancy and lactation. The control diet contained 4.59 g of n-3 per 100 g of total FA, and the enriched diet contained 14.9 g of n-3 per 100 g of total FA. From weaning (30 d of age) to slaughter (60 d), the litters (12 per diet; 8 kits each) continued fed the corresponding experimental diet. There were no differences ( > 0.05) between groups in ADFI, ADG and G:F ratio during the growing period. At slaughter, BW, full gastrointestinal tract weight, carcass yield, meat color and pH, drip loss percentage, content of scapular fat and tissue composition of the left hind leg were similar between groups ( > 0.05), but perirenal fat was lower ( = 0.020) and skin weight and abdominal fat tended to be lower ( = 0.055 and = 0.063, respectively) in enriched rabbits than in control ones. Total PUFA content in both LM and perirenal fat was greater ( = 0.021 and < 0.001, respectively) in enriched rabbits, that also showed lower n-6/n-3 ratios in LM (1.61 vs. 5.80; < 0.001) and perirenal fat (4.71 vs. 12.0; < 0.001) than those fed the control diet. Cecal concentrations of total VFA were greater ( < 0.001) in enriched than in control group at 30, 45 and 60 d of age, but diet did not affect ( ≥ 0.332) VFA profile, with the exception of a lower ( = 0.013) proportion of minor VFA (sum of isobutyrate, isovalerate, and valerate) in control group. Diet did not affect ( > 0.255) either pH and NH-N concentrations in the cecum or ileal morphology (crypt depth and villi length). The results showed that dietary fish oil supplementation enhanced beneficial long-chain n-3 FA and decreased n-6/n-3 ratio in rabbit meat and fat, being healthier for human consumption, without having negative effects on growth performance, cecal fermentation, and ileal morphology or carcass characteristics.

This study was conducted to evaluate the pilot-scale production of microencapsulated in a 500-L fermenter using emulsion and gelation and to assess the effect of the products on the growth performance, antioxidant activity, immune function, and cecal microbiota in Arbor Acres broilers. A total of seven hundred 1-d-old male Arbor Acres broilers were randomly assigned to 7 dietary treatments with 5 replicate pens per treatment and 20 broilers per pen. The dietary treatments were as follows: 1) basal diet (CON), 2) basal diet containing 0.1% Aureomycin (ANT), 3) basal diet containing unencapsulated at a dose of 1 × 10 cfu/kg of feed (P1), 4) basal diet containing unencapsulated at a dose of 1 × 10 cfu/kg of feed (P2), 5) basal diet containing 0.01% empty microcapsules (CAP), 6) basal diet containing microencapsulated at a dose of 1 × 10 cfu/kg of feed (CAPP1), and 7) basal diet containing microencapsulated at a dose of 1 × 10 cfu/kg of feed (CAPP2). The feeding experiment included 2 phases: the starter phase from d 1 to 21 and the grower phase from d 22 to 42. The results showed that a 500-L fermenter could produce 20.73 ± 4.05 kg of microcapsules with an approximate diameter of 549 μm. The feeding experiment showed that ADG of broilers in CAPP1 was significantly ( < 0.05) greater than that in CON and CAP throughout the feeding period, whereas the ratio of feed to gain (G:F) was significantly ( < 0.05) lower. Broilers in P1, P2, CAPP1, and CAPP2 had significantly ( < 0.05) greater levels of total superoxide dismutase, catalase, IgG, and cluster of differentiation 3 than those in CON. Furthermore, broilers in CAPP1 had significantly ( < 0.05) greater richness and diversity of intestinal microorganisms, particularly of , than those in all other dietary treatments. In summary, our results indicate that large-scale microencapsulation of microbial cells can be achieved using emulsion and initial gelation and that the dietary administration of microencapsulated can significantly enhance the growth performance, immune function, cecum microbial community, and overall health of broilers.

Salmonella enterica serovar Enteritidis is one of the leading causes of food-borne salmonellosis in humans. Poultry is the single largest reservoir, and the consumption of incorrectly processed chicken meat and egg products is the major source of infection. Since 2006, the use of antibiotics as growth promoters has been banned in the European Union, and the dietary inclusion of β-galactomannans (βGM) has become a promising strategy to control and prevent intestinal infections. The aim of this study was to investigate the effect of various βGM-rich products on intestinal morphology in chickens challenged with Salmonella Enteritidis. To assess this effect, a total of 280 male Ross 308 chickens were studied (40 animals per treatment housed in 5 cages). There were 7 treatments, including controls: uninoculated birds fed the basal diet (negative control) and inoculated birds fed the basal diet (positive control) or the basal diet supplemented with Salmosan (1 g/kg), Duraió gum (1 g/kg), Cassia gum (1 g/kg), the cell walls of Saccharomyces cerevisiae (0.5 g/kg), or the antibiotic colistine (0.8 g/kg). The birds were fed these diets from the d 1 to 23, except the animals in the colistine group, which were fed the diet containing the antibiotic only from d 5 to 11. The inoculated animals were orally infected on d 7 with 10(8) cfu of Salmonella Enteritidis. Bird performance per replicate was determined for the whole study period (23 d), and the distal ileum and cecal tonsil of 5 animals per treatment (1 animal per replicate) were observed at different magnification levels (scanning electron, light, and laser confocal microscopy). In the images corresponding to the treatments containing βGM we observed more mucus, an effect that can be associated with the observation of more goblet cells. Moreover, the images also show fewer M cells, which are characteristic of infected animals. Regarding the morphometric parameters, the animals that received Duraió and Cassia gums show greater (P = 0.001 and P = 0.016, respectively) villus length compared with the animals in the positive control, thus indicating the capacity of these products to increase epithelial surface area. However, no effect (P > 0.05) on microvillus dimensions was detected. In conclusion, the results obtained indicating the beneficial effects of these βGM on intestinal morphology give more evidence of the positive effects of these supplements in poultry nutrition.

This study aimed at comparing various diets predicted to induce different stimulations of the cecal microbial activity of the young rabbit fed ad libitum from 16 to 70 d of age: i) a diet enriched with rapidly fermentable fiber expected to stimulate the cecal microbial activity (RFF group); ii) a control diet with a standard composition (C group); iii) and the same control diet with tiamulin and apramycin antibiotics, expected to inhibit the microbial activity (C+AB group). A total of 398 rabbits were used from 42 litters and weaned at 28 d of age. An in vivo digestibility trial was performed on 36 rabbits of 42 to 46 d of age housed in individual metabolic cages. The feed intake and growth rates were lower in the RFF group compared with the C+AB group (-15% in ADFI and -11% in ADG, P<0.001), with a lower weight of -183 g at 70 d (P<0.001). No significant difference was found on ADG and final BW between the RFF and the C groups, but the RFF diet allowed a better G:F ratio at postweaning (P<0.01). The digestion of soluble fiber (total dietary fiber minus NDF) was greater for the RFF group. The C+AB diet had a positive effect on the postweaning morbidity rate (P<0.05) but did not affect the mortality rate and the health risk index (morbidity and mortality). Conversely, the RFF diet appeared to reduce the mortality rate compared with the C+AB diet, especially before 41 d of age. Concerning the cecal microbial activity, a supply of RFF in the diet increased the cecal VFA concentrations (+28% vs. C+AB and +22% vs. C, P<0.001) and lowered the pH. The VFA pattern was affected at 45 and 60 d, with a dominance of acetate in the RFF group (+4% vs. C+AB and C groups, P<0.001) instead of butyrate in the C+AB and C groups (-3.6% and -5% vs. C+AB and C, respectively, P<0.001). Antibiotics addition (C+AB group) reduced the VFA concentration, but only after weaning (-25% at 45 d of age) without changing the fermentation pattern. In conclusion, early intake of RFF in young rabbits stimulated the cecal microbial activity, and reduced the voluntary feed intake, leading to a reduced G:F ratio.

The aim was to evaluate the effects of feeding resistant potato starch (RPS) as a natural source of resistant starch to weaned pigs for 28 d immediately after weaning. Sixty piglets (Yorkshire-Landrace × Duroc) weaned at 21 ± 2 d (1:1 male:female) with an initial BW of 7.2 ± 0.78 kg were assigned in a completely randomized design to 1 of 5 dietary treatments to give 6 observations per treatment and 2 pigs per pen. Dietary treatments consisted of a negative control corn-soybean meal-wheat-wheat middlings-based diet (NC; no antimicrobial agents added) or the NC supplemented with RPS either as powder or in capsules and each included at 0.5 or 1.0% as a top-dressing on each day. Diets were formulated to meet 1998 NRC specifications. Pigs were offered the experimental diets on an ad libitum basis for 28 d and water was available at all times. The ADG, ADFI, and G:F were determined weekly. Fecal score was determined daily for 14 d after weaning. At the conclusion of study, 1 pig from each pen was randomly selected and euthanized (n = 6 per treatment) to determine visceral organ weight, digesta pH, VFA, and ammonia N (NH3-N) concentrations. Resistant potato starch supplementation improved (P < 0.001) fecal score, and pigs offered 1.0% RPS had more solid feces (P < 0.05) than those offered 0.5% RPS during the first 14 d after weaning, independent of the form of RPS. Resistant potato starch supplementation decreased (P < 0.05) ileal and cecal digesta pH regardless of the levels of RPS or mode of delivery. The total VFA concentrations in cecal digesta were greater (P < 0.05) but the molar proportion of branched-chain fatty acids were lower (P < 0.05) for pigs fed the RPS-containing diets compared with those fed the NC, irrespective of the RPS levels or the form of RPS. However, there were no differences (P > 0.10) in visceral organ weights, growth performance, and digestibilities of DM, CP, Ca, and P among treatments. The results of this experiment indicate that supplementing a weaner pig diet with at least 0.5% RPS independent of mode of delivery has the potential to enhance outcomes characteristic of a functional gut in weaned pigs without adverse effects on growth.

The objective of this 49-d experiment was to test effects of cecal oxytetracycline (OTC) infusion, and dietary avidin and biotin supplementation on the biotin status of nongravid gilts. Twenty-eight crossbred gilts with an initial age of 160 d and BW of 120 kg were surgically fitted with a T-cannula in the terminal ileum, a cecal fistula, and an indwelling catheter in the anterior vena cava, and allotted to 7 dietary treatments. Treatments with the basal semipurified (SP) diet fed at 1.86 kg/d were: SP-1, negative control; SP-2, positive control with 270 μg of biotin/kg; SP-3, with spray-dried egg albumen (EA, 100 g/d) and OTC (2.56 g/d by cecal infusion); and SP-4, with EA, OTC, and 700 μg of biotin/kg. Treatments with the basal corn-soybean meal (CS) diet fed at 1.80 kg/d were: CS-1, negative control; CS-2, with EA and OTC; and CS-3, with EA, OTC, and 700 μg of biotin/kg. Response criteria were: fecal bacteria counts; plasma concentrations of biotin, glucose, and urea N (PUN); liver pyruvate carboxylase (PC) activity; kidney and epithelial tissue histology; ileal and fecal biotin concentrations; ileal and total tract N and energy utilization; daily gilt observation; and BW gain. Blood samples were collected every 7 d with serial samples collected on d 49. Total urine collections and fecal grab samples were made twice daily from d 44 to 49. Gilts were killed on d 50 and liver, kidney, and skin samples were collected. No gilts had symptoms of biotin deficiency. There were no treatment differences in BW gain, plasma glucose concentrations, liver PC activity, kidney and epithelial tissue histology, or fecal bacteria counts. Ileal and total tract N and energy digestibilities (%) did not differ among treatments within the same protein source, with greater (P ≤ 0.05) values for gilts on the SP treatments than the CS treatments. However, N retained/N absorbed and N retained/N intake (%) were less (P ≤ 0.05) and PUN concentrations were greater (P ≤ 0.05) for SP treatments with cecal OTC infusion. The overall fecal biotin concentration mean was 2.6-fold greater than the overall ileal biotin concentration mean. In conclusion, no gilts in the current experiment became biotin deficient because the biotin requirements were met primarily by microbial synthesis and absorption of biotin from the distal small intestine and large intestine, with corn and soybean meal contributing endogenous biotin. Therefore, supplementation of diets for gilts entering the breeding herd with 100% of the current NRC biotin requirement for sows is adequate.

The objective of this study was to investigate the effects of chitosan (CHI) on ruminal and cecal fermentation and on apparent digestibility in sheep. In a first trial, 4 ruminally fistulated sheep fed an alfalfa hay and concentrate diet formulated to meet 1.2 times their maintenance energy requirements were assigned to 2 treatments [no-additive control (CTR), or 136 mg/kg of BW of CHI] for 19 d in a 2 x 2 crossover design. Samples of ruminal fluid and feces were taken for VFA and NH(3)-N concentrations. At the end of each period of the crossover, ruminal fluid was used as inoculum for batch cultures (24 and 96 h), and the effects on rate and extent of gas production and on fermentation variables for starch, cellulose, and the same diet fed to the animals were calculated. In a second trial, 4 sheep fed the alfalfa hay and concentrate diet were assigned to 2 treatments (CTR and CHI), as for the first trial, but this time for 14 d in a 2 x 2 crossover design. Apparent digestibility was studied. In the first trial, in terms of ruminal fermentation, CHI did not affect (P = 0.12) total VFA concentration or acetate proportion, but increased propionate proportion (P = 0.004) and propionate-to-acetate ratio (C3:C2; P = 0.007) and decreased branched-chain VFA (BCVFA) proportion (P = 0.003) and NH(3)-N concentration (P = 0.045). In feces, CHI decreased total VFA concentration (P = 0.01) and acetate (P = 0.045) and butyrate (P = 0.025) proportions, and increased propionate (P = 0.04), valerate (P = 0.01), and BCVFA (P = 0.032) proportions and C3:C2 ratio (P = 0.045). In batch cultures, when starch was used as substrate, CHI decreased acetate proportion (P = 0.016) and methane production (P = 0.03) and increased propionate and valerate proportions and C3:C2 ratio (P < 0.001). When cellulose was used as substrate, CHI decreased in vitro OM digestibility (P = 0.033), total VFA concentration, propionate proportion (P < 0.001), C3:C2 ratio (P = 0.006), methane production (P < 0.001), NH(3)-N concentration (P = 0.019), and gas production rate (P = 0.002), and increased butyrate (P = 0.029) and BCVFA (P = 0.004) proportions and pH (P < 0.001). When the alfalfa hay and concentrate diet was used as substrate, CHI decreased butyrate (P < 0.001) and BCVFA (P = 0.008) proportions, methane (P = 0.005) and asymptotic gas production (P = 0.02), and gas production rate (P = 0.05). In the second trial, CHI decreased NDF apparent digestibility (P = 0.09). In conclusion, CHI shifted ruminal fermentation toward energetically more efficient routes, without reducing OM apparent digestibility.

We evaluated spray-dried animal plasma (SDAP) as an alternative to antimicrobial medication with colistin sulfate in weanling pigs challenged with Escherichia coli K99. Forty-eight piglets weaned at 24 d of age were distributed into 12 pens, and each pen was assigned to one of four dietary treatments. All the piglets were given an oral dose of 5 x 10(7) cfu of E. coli K99 at weaning. The dietary treatments followed a factorial arrangement with two levels of SDAP (0 and 7%) and two levels of colistin (0 and 300 mg/kg of diet). The ADG and ADFI were measured on d 7 and 14 of trial. Three piglets from each treatment were killed on d 7 and 14 to remove the small intestine, and to obtain ileal and cecal digestive contents. The inclusion of SDAP improved ADG by 68 g (P < 0.05) and ADFI by 41 g (P < 0.10) in wk 1 of trial. During wk 2, SDAP improved ADG by 41 g (P < 0.10) and gain:feed ratio (G:F) by 25% (P < 0.01). On the other hand, whereas colistin had no effect on performance in wk 1, it improved ADG by 102 g (P < 0.01), ADFI by 62 g (P < 0.01), and G:F by 26% (P < 0.01) in wk 2. Over the 14 d of the trial, ADG was improved by 54 (P < 0.05) and 75 g (P < 0.05), and G:F was improved by 35 (P < 0.05) and 32% (P < 0.05) due to SDAP and colistin, respectively. There was interaction between colistin and SDAP for ADFI in wk 2 and between d 0 to 14 (P < 0.05), which indicates that their effects were not additive. The use of colistin was advantageous in the maintenance of the integrity of the intestinal mucosa of the pigs, as suggested by a small intestine that was 93 g heavier (P < 0.10) and with the tallest villi 106 microm longer (P < 0.10) than in pigs without colistin. The inclusion of SDAP in the diet favored the growth of lactobacilli in the ileum (P < 0.10) and the cecum (P < 0.05), whereas colistin reduced the number of enterococci in the cecum (P < 0.05) and of Escherichia coli both in the ileum and the cecum (P < 0.001). These results suggest that SDAP may be an alternative to medicated feed with antibiotics since it provided a level of protection against an experimental challenge with E. coli K99 similar to that obtained with colistin, an antibiotic of proven efficacy. The current situation in which the use of antimicrobials in animal feeding is being questioned should encourage further investigation into the use of SDAP as a means of preventing disease in pigs at weaning.

Acute laminitis can be induced experimentally in horses by the administration of carbohydrate, resulting in fermentation within the cecum and ischemia-reperfusion of the digits. The products of fermentation that trigger acute laminitis are as yet unknown; however, compounds such as amines might play a role due to their potential vasoactive properties. The objectives of this study were to quantify the amines present in equine cecal contents and to use a model of carbohydrate overload in vitro to test the hypothesis that carbohydrate fermentation is associated with increased amine production. Cecal contents from each horse were divided into aliquots and incubated anaerobically with either cornstarch or inulin (a form of fructan carbohydrate; both 1 g/100 mL). The pH was measured and samples were taken at the same time for amine measurement by HPLC at 2-h intervals over a 24-h period. In a second set of experiments, the effects of the antibiotic virginiamycin (1 mg/100 mL), calcium (CaPO4; 0.3 g/100 mL), and plant steroidal saponin (Yucca schidigera extract; 0.1 g/100 mL) were examined on pH and amine concentrations in cecal contents incubated with starch or inulin. Both starch and inulin caused significant time-dependent falls in pH, from 6.7 +/- 0.1 at 0 h to 5.2 +/- 0.1 (starch) and 5.0 +/- 0.1 (inulin) at 24 h. Fermentation of carbohydrate was also associated with increased production of phenylethylamine and isoamylamine (two- to threefold increases) as well as putrescine and cadaverine (1.5- to twofold increases). Virginiamycin inhibited the fall in pH and increases in production of phenylethylamine and isoamylamine, while calcium phosphate moderated the changes in pH only. Yucca schidigera extract was without effect. These data show that fermentation of carbohydrate by equine cecal microbiota may lead to increased production of amines.

Addition of fat to the diet of the equine is a popular method of increasing energy density of the diet while reducing feed intake. Reducing feed intake is of interest to race horse trainers because additional feed is seen as additional weight and, therefore, a hindrance to performance. Limited information is available regarding the interactions of fat with other dietary components, particularly fiber, in the equine digestive system. The effect of dietary fat on in vitro nutrient disappearance in equine cecal fluid was studied in Exp. 1 using a split-plot design within a 2 x 2 Latin square. Two ponies were fed alfalfa (ALF) alone or alfalfa plus 100 g/d corn oil. Five substrates were used to determine in vitro DM disappearance, OM disappearance, NDF disappearance, and total dietary fiber (TDF) disappearance. The substrates included: ALF, tall fescue (TF), red clover (RC), soybean hulls (SBH), and rolled oats (RO). Fat supplementation did not affect in vitro DM, OM, or NDF disappearance. Addition of fat to the diet increased (P < 0.05) the disappearance of NDF in RO. Among substrates, in vitro DM and OM disappearance were highest (P < 0.05) for RO, followed by SBH, ALF, RC, and TF. In vitro NDF and TDF disappearance were highest (P < 0.05) for SBH, followed by RO, ALF, RC, and TF. In Exp. 2, the effects of varying levels of fat on nutrient intake and total tract digestibility were examined using a 4 x 4 Latin square design. Four mature mares were fed a 60% forage-40% concentrate diet containing different concentrations of fat: 0% supplemental fat control (C); 5% supplemental corn oil (5% CO); 10% supplemental corn oil (10% CO); or 15% supplemental corn oil (15% CO). Treatment did not affect intake of the concentrate portion of the diet or CP, gross energy, or NDF intake. Mares consuming the C diet had the highest (P < 0.05) intake of alfalfa cubes, DM, and OM, followed by those on the 10, 5, and 15% CO treatments, respectively. Treatment did not affect nutrient digestibility. Mares consuming the 15% CO diet had the highest (P < 0.05) fat digestibility, whereas those consuming C had the lowest fat digestibility. Fat in the form of CO generally had little effect on in vitro and in vivo nutrient digestibilities in horses.

The influence of fiber source on fiber digestion in rabbits was investigated. Six fibrous feedstuffs with wide differences in chemical composition and particle size were selected: paprika meal, olive leaves, alfalfa hay, soybean hulls, sodium hydroxide-treated barley straw, and sunflower hulls. Six diets were formulated to contain one of these ingredients as the sole source of fiber. To avoid nutrient imbalances, fiber sources were supplemented with different proportions of a fiber-free concentrate, based on soy protein isolate, wheat flour, lard, and a vitamin and mineral mix, to obtain diets containing at least 3% nitrogen and 5% starch. Daily soft feces excretion, and its NDF, and total and microbial nitrogen content were determined in 60 fattening rabbits (10 per diet). Seven days after the last cecotrophy control, the same animals were used to determine weight of stomach, cecum and their contents, and cecal fermentation traits (pH, VFA and ammonia concentrations, and buffer properties of cecal contents). Stepwise regression analysis showed a positive effect (P < .001) on soft feces excretion, total and microbial nitrogen concentrations in soft feces, cecal acidity, and total VFA in the cecum of dietary pectic constituents (2.9, 3.5, 2.5, .9, and 6.6%) and proportion of fine particles (< .315 mm) (1.8, .9, 1.3, .15, and .9%) per each increment of one percentage unit of the independent variables. Proportion of fine particles also increased weight of cecal contents (P < .001). Soft feces excretion and weight of stomach and of its contents increased (P < .001) by 5.2, 2.8, and 10.2% per each percentage unit increment of proportion of large particles (> 1.25 mm). Degree of lignification of NDF decreased total nitrogen concentration in soft feces and cecal VFA concentration (P < .001). Source of fiber affected cecal pH not only by its influence on the cecal concentrations of the final products of fermentation, but also through its effect on the pH of dry cecal contents (P < .001). The latter was negatively correlated with dietary proportion of fine particles, degree of lignification of NDF, and base-buffering capacity of dry cecal contents (r = -.52, -.37, and -.49, respectively). From these results, we conclude that pectic constituent concentration, degree of lignification of NDF, and particle size are the variables that best characterize the influence of the source of fiber on soft feces excretion and cecal fermentation traits in rabbits.

We determined the effects of lignosulfonate (LS) on nutrient digestibility and on hindgut fermentation characteristics using 80 adult male Sprague-Dawley rats fed a control diet or a diet containing 3% (dry matter basis) of seven selected LS fractions. Lignosulfonate fractions were divided into three categories: two fractionated whole calcium spent sulfite liquors (CaSSL) and one low-molecular-weight permeate of CaSSL designated as WholeLS 1, 2, and 3, respectively; two extracted sodium LS (NaLS) fractions denoted as HighLS 1 and 2 (high percentage of NaLS); and two concentrated sugar solutions designated as LowLS 1 and 2 (low percentage of NaLS). All diets containing LS were less digestible (P < .001) than the control diet. Lignosulfonate treatment had a variable effect on short-chain fatty acid concentration except for LowLS 1, which tended to enhance butyrate concentration. Cecal organ weights were greater (P < .001) for LS treatments, but there was no difference in colonic organ weights. All cecal and colonic pH values, except the cecal pH for HighLS 2, were lower (P < .001) for LS treatment groups. Colonic Bifidobacterium increased (P < .005) with WholeLS 1 and 3 and HighLS 2 treatments. Cecal Lactobacillus levels were increased (P < .001) by WholeLS 1 and 2, LowLS 2, and HighLS 2. Results show that ingestion of selected LS fractions can modify digestive physiology and gastrointestinal tract characteristics of rats.

Six crossbred male pigs (40 kg) with cecal cannulas were randomly allotted to three treatments for evaluation of the effect of three levels of dietary Solka-floc (2, 10 and 18%) on cecal functionality. Samples were collected every fourth day for 40 days. Blood was obtained 4 hr after the morning feeding, and cecal contents were sampled at 3-hr intervals during the 12-hr period between the morning and evening meals. Blood urea nitrogen was not affected by dietary cellulose, and it remained constant throughout the experiment. Dry matter and cellulose digestibilities were reduced (P < .05) by the increase in dietary cellulose, suggesting a maximum cellulose digestion capability of about 35 g/pig daily. A definite daily pattern was observed for cecal ammonia nitrogen. It reached a maximum 6 hr after feeding. Cecal volatile fatty acid (VFA) concentrations were not affected by dietary cellulose. After 40 days, 150 mg/kg body weight of neomycin sulfate was administered daily for 8 days, 100 mg in the feed and 50 mg into the cecum via the cannula. The antibiotic resulted in a decrease (P < .01) in cecal VFA concentrations, an increase (P < .01) in cecal ammonia N level and a complete arrest of cellulose digestion.