Raw Potato Starch Research Articles

The <i>in vitro</i> caecal fermentation of different starch sources in rabbits

The objective of our study was to extend the knowledge of microbial fermentation of starch in the rabbit caecum using the in vitro gas production technique. Different sources of starch (wheat and maize grain, raw and cooked potato) and different starch isolates (wheat, maize and potato starch) were incubated with inoculum, prepared from rabbit caecum content. The gas production parameters such as total potential gas production (parameter “B”), gas production till 10 h of incubation (Gas10), maximum fermentation rate (MFR) and time of maximum fermentation rate (TMFR) were estimated with Gompertz model and were significantly affected by the substrata. Differences between maize grain and maize starch were small: MFR and TMFR were not different, while Gas10 of maize starch was higher than from maize grain (5 and 3 ml/kg DM, respectively; P < 0.05). MFR of wheat starch was higher than that of wheat grain (3.1 and 2.4 ml/h, respectively; P < 0.05), but reached maximum rate later (TMFR: 12.4 and 10.9 h, respectively; P < 0.05) and had lower Gas10 (6 and 9 ml/kg DM, respectively; P < 0.05). The fermentation of cooked potato reached the TMFR after 8.5 h of incubation and had the highest MFR (2.9 ml/h) and Gas10 (16 ml/kg DM) of all substrata. The MFRs of raw potato and potato starch were similar (2.1 and 2.3 ml/h, respectively), although TMFR and Gas10 of raw potato were shorter and higher than those of potato starch (TMFR of 10.7 and 17.2 h and Gas10 of 10 and 1 ml/kg DM, respectively; P < 0.05).

Salt-independent thermophilic α-amylase from Bacillus megaterium VUMB109: An efficacy testing for preparation of maltooligosaccharides

An amylase (est. Mw 150kDa) was purified 27.39-folds from the culture broth of Bacillus megaterium VUMB109. The purified enzyme was not inhibited by p-chloromercuro benzoate and iodoacetamide (10mM), it rapidly decolorized the blue color of starch–iodine complex and produced α-anomeric products from starch hydrolysis, thus, it is an endo-attacking α-amylase. The enzymatic activity was not affected by any metal ion and EDTA, therefore, it is not in the class of metalloenzyme. The purified α-amylase showed higher affinity (Km=1.5μM; Vmax/Km=0.38 and Kcat/Km=2.5×106) to starch than other tested substrates like amylose, amylopectin and glycogen. Maltooligomer mixture with high proportion of maltopentaose (G5) and maltotriose (G3) was produced during hydrolysis of starch, amylopectin and amylose. It exhibited high degree of hydrolysis on raw potato starch than wheat, rice and corn starches. Thus the studied α-amylase could be exploited as a useful catalyst in the bioprocessing of maltooligomer mixture as food supplement for baby and aged people.

Influence of different carbohydrate composition in barley varieties on Salmonella Typhimurium var. Copenhagen colonisation in a “Trojan” challenge model in pigs

Based on previously performed in vitro studies, which showed that hulless barley varieties could reduce large intestinal Salmonella Typhimurium var. Copenhagen proliferation in pigs, two in vivo experiments were conducted to prove these observations. In Experiment (Exp.) 1, 126 weaning piglets were randomly allocated into pens of seven animals each and fed one of six experimental diets. Three diets contained (75% as-fed) one of three hulless barley varieties with β-glucan (BG) contents ranging from 5 to 11% and amylose from 5 to 40%, and two diets contained a low BG and amylose hulless barley supplemented with isolated barley BG or raw potato starch. A hulled barley diet served as a control. Two piglets per pen (“Trojan” pigs) were orally infected with Salmonella Typhimurium var. Copenhagen (ST). The remaining five pigs per pen were designated “Contact” pigs. The ST shedding was determined over one week after infection. On day 6, the two Trojans and two random Contacts from each pen were euthanised and intestinal contents and mesenteric lymph nodes cultured for ST. Intestinal volatile fatty acids and microbial composition were determined. In Exp. 2, 126 piglets were assigned to one of three diets based on hulled or hulless barleys. The timeline, infection, sampling and analyses were similar as in Exp. 1 except samples were taken from four Contact pigs. Hulless barley varieties with high BG and amylose tended to decrease ST persistence in Exp. 1. Clostridia from cluster I in the colon were reduced with high amylose hulless barley or diets supplemented with potato starch (p < 0.05), whereas other microbial groups were not. Propionate increased (p < 0.05) and acetate decreased (p < 0.05) with hulless barley inclusion. Exp. 2 revealed a reduced ST shedding and reduced number of clostridia for high BG hulless barley as compared to common hulled barley and a low BG variety (p < 0.05). In conclusion, high BG hulless barley do not prevent ST colonisation but might help to reduce transmission in pigs, likely by supporting an intestinal environment limiting growth of this zoopathogen.

バレイショ澱粉を配合した低タンパク質飼料の給与が肥育豚の窒素排泄量およびアンモニア揮散量に及ぼす影響

バレイショ生澱粉（RPS）を配合した低タンパク質飼料の給与が肥育豚の窒素排泄量およびアンモニア揮散量に及ぼす影響を調査した．飼料反転法による窒素出納試験に 4頭の去勢雄（WLD, 64.0kg）を，またウインドウレス豚舎内でのアンモニア揮散量の測定試験には 8頭の去勢雄（WLD, 70.0kg）を用い，いずれの試験でも標準的肥育飼料（CP 15.7%）を給与する対照区とRPSを20%配合した低CP飼料（CP 11.6%）を給与するRPS区を設定した．RPS区では糞への窒素排泄量は対照区より多い（P<0.01）ものの，尿への窒素排泄量と糞尿への総窒素排泄量は少なくなった（P<0.01）．糞尿混合物からの in vitro アンモニア揮散量（P<0.05）および豚舎内アンモニア濃度（P<0.01）はRPS区で低くなった．一方，試験期間における肥育豚の増体量，飼料摂取量および飼料要求率には両区間の差は認められなかった．以上の結果から，RPSを配合した低タンパク質飼料の給与は肥育豚の発育に影響することなく，尿への窒素排泄量および豚舎内アンモニア濃度を大幅に低減できる可能性が示された．

Enhanced production of α‐amylase from Bacillus subtilis subsp. spizizenii in solid state fermentation by response surface methodology and its evaluation in the hydrolysis of raw potato starch

AbstractThis is an attempt to lower the cost of starch hydrolysis by the discovery of new generation α‐amylase. A natural isolate of Bacillus subtilis subsp. spizizenii was capable of producing appreciable amounts of raw potato starch digesting α‐amylase in solid state fermentation of wheat bran. The enzyme productivity has been substantially enhanced by supplementing various nutrients and statistically studying their interactions by response surface methodology. A central composite design for amylase production system elucidated a wheat bran‐based medium supplemented with soybean meal, threonine, and B‐complex vitamins predicting a yield of 521 391 U/g dry solids. The enzyme preparation could effectively digest 5–15% suspension of insoluble potato starch in 6 h revealing the dextrose equivalent of 32–44. The supplementation of a glucoamylase preparation, thereafter, brought about complete saccharification. The yield achieved in the statistically optimized amylase system may be one of the best to date and its capability in directly liquefying raw potato starch granules makes this study novel.

Influence of different levels and sources of resistant starch on faecal quality of dogs of various body sizes

In dry-extruded canine diets, starch ileal digestibility varies with the starch source, amount and processing parameters. Starch that escapes duodeno-ileal digestion can affect faecal quality by stimulating colonic bacterial fermentation. The aim of the present study was to assess the effect of various resistant starch (RS) sources and levels on the faecal score of dogs of different breeds and sizes. A total of twenty-one healthy adult female dogs (body weight ranging 5.0-30.6 kg) were used. The maintenance diet for the dogs was supplemented with increasing amounts of RS from two sources: high-amylose starch from maize (to 2.5, 4.3 and 7.4 % RS) and raw potato starch (to 7.4 and 11.4 % RS). Each level of RS was tested over a 7 d period followed by a 7 d washout period. Faecal scores were evaluated by one person using a scale ranging from 1 (for hard and dry faeces) to 5 (for liquid stools). Faeces were considered 'optimal' at scores of 2.5-3.0, 'acceptable' at scores of 3.0-3.75 and 'unacceptable' at scores >3.75. Small dogs showed very little sensitivity to RS based on the faecal score, while large dogs were quite responsive to RS supplementation. These results suggest that small dogs are poor models for assessing the effect of starch sources on ileal digestibility. They also indicate that a low RS content (strongly affected by source and processing) is an important factor for ensuring an optimal faecal score in large breed dogs.

English

A new amylase gene APGA1 was cloned from Aureobasidium pullulans NRRL 12974 and expressed in Pichia pastoris . This is the first report on cloning and expression of amylolytic gene from the industrially important microorganism A. pullulans . The purified recombinant protein with MW of 66 kDa and specific activity of 298.02 Umg -1 protein was verified as a glucoamylase by its hydrolytic mode. This recombinant glucoamylase with optimal pH of 4.5, and temperature of 60°C, showed good hydrolytic activity against raw potato starch. At 60°C, 83.1% of raw potato starch slurry (150 gl -1 ) was hydrolysed into glucose by 0.1 U mg -1 starch purified recombinant glucoamylase in less than 2.5 h. This is the highest raw starch hydrolysis efficiency report about recombinant fungal glucoamylase. This useful property indicated that this glucoamylase may find important applications in the starch saccharification industry and in bioethanol production. Key words: Glucoamylase, Aureobasidium pullulans, expression, raw starch degradation.

Easily fermentable carbohydrates reduce skatole formation in the distal intestine of entire male pigs

Two experiments were conducted to evaluate the effects of feeding different sources of easily fermentable carbohydrates to entire male pigs during the last weeks before slaughter. In Exp. 1, 48 entire male pigs (21.8 and 100.5kg initial and final body weight, respectively) were used to evaluate the effect of adding 0, 3, 6, or 9% chicory inulin (containing 70% inulin) to diets during the last 30days before slaughter on skatole concentration in the hind-gut and adipose tissue and on the composition of microbiota and mucosa morphology in the hind-gut. In Exp. 2, 66 entire male pigs (31.0 and 112.0kg initial and final body weight, respectively) were used to evaluate the effect of adding 20% raw potato starch to diets as a top dressing or adding increasing levels of potato starch (0, 5, 10, 15%, and 20%) to diets prior to pelleting during the last 14days before slaughter on skatole concentrations in hind-gut and adipose tissue and on the composition of microbiota in the hind-gut. Results from Exp. 1 showed a significant reduction in skatole levels in colon and rectum with increasing dietary levels of inulin (linear, P≤0.002). In these diets there was also a reduction of enterobacteria counts in colon descendens (linear, P=0.04) and rectum (linear, P=0.02), and a tendency towards reduced levels of Enterococcus spp. in colon descendens (linear, P=0.09) and rectum (linear, P=0.08). Results from Exp. 2 showed that adding raw potato starch as a top dressing reduced skatole levels in rectum and adipose tissue compared with the control, while adding increasing levels of potato starch to diets prior to pelleting did not affect skatole levels. Adding potato starch as a top dressing or to diets before pelleting did not affect the cultured bacteria in the hind-gut of pigs. Feeding inulin or potato starch did not affect mucosal epithelial cell counts in the cecum or colon in Exp. 1 and Exp. 2, respectively. In conclusion, feeding increasing levels of chicory inulin to entire male pigs during the last period before slaughter reduced the level of skatole in the distal intestine and in adipose tissue, feeding pelleted diets containing up to 20% potato starch had no effect, while feeding 20% raw potato starch as top dressing reduced the level of skatole in the distal intestine and the adipose tissue of the entire male pigs.

Characteristics of raw starch degrading α‐amylase from Bacillus aquimaris MKSC 6.2 associated with soft coral Sinularia sp.

AbstractPartially purified α‐amylase from Bacillus aquimaris MKSC 6.2, a bacterium isolated from a soft coral Sinularia sp., Merak Kecil Island, West Java, Indonesia, showed an ability to degrade raw corn, rice, sago, cassava, and potato starches with adsorption percentage in the range of 65–93%. Corn has the highest degree of hydrolysis followed by cassaca, sago potato and rice, consecutively. The end products of starch hydrolysis were a mixture of maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and small amount of glucose.

Production and properties of the highly efficient raw starch digesting α-amylase from a Bacillus licheniformis ATCC 9945a

Highly efficient raw starch digesting α-amylase was produced after 24h of batch fermentation of Bacillus licheniformis ATCC 9945a in laboratory bioreactor at 37°C. The enzyme was purified by gel filtration chromatographies with 6-fold increase of specific activity and 38% recovery and showed a molecular mass of 31kDa by SDS-PAGE. The purified enzyme had an optimum pH of 6.5 and optimum temperature of 90°C. The purified α-amylase in the presence of CaCl2 retained 55% of its activity after 6h of incubation at 70°C. Co2+, Ni2+ and Ca2+ slightly stimulated, while Hg2+ completely inhibited α-amylase activity. Hydrolysis rates of raw triticale, wheat, potato, horseradish and corn starches, at 1% concentration were 63, 60, 59, 52 and 37%, respectively, in a period of 4h. The properties of the purified enzyme proved its high efficacy for digesting diverse raw starches below gelatinization temperature and, hence, its potential commercial value to use as an industrial enzyme.

Response of Nursery Pigs to a Synbiotic Preparation of Starch and an Anti-Escherichia coliK88 Probiotic

Postweaning diarrhea in pigs is frequently caused by enterotoxigenic Escherichia coli K88 (ETEC). The aim of this study was to test the efficacy of E. coli probiotics (PRO) in young pigs challenged with E. coli K88. We also tested the synbiotic interaction with raw potato starch (RPS), which can be used as a prebiotic. Forty 17-day-old weaned piglets were randomly assigned to four treatments: treatment 1, positive-control diet (C), no probiotics or RPS but containing in-feed antibiotics; treatment 2, probiotic (PRO), no feed antibiotics plus a 50:50 mixture of probiotic E. coli strains UM-2 and UM-7; treatment 3, 14% RPS, no antibiotics (RPS); treatment 4, 14% RPS plus a 50:50 mixture of probiotic E. coli strains UM-2 and UM-7, no antibiotics (PRO-RPS). The pigs were challenged with pathogenic E. coli K88 strains on day 7 of the experiment (24-day-old pigs) and euthanized on day 10 of the experiment (35-day-old pigs). Probiotic and pathogenic E. coli strains were enumerated by selective enrichment on antibiotics, and microbial community analysis was conducted using terminal restriction length polymorphism analysis (T-RFLP) of 16S rRNA genes. The combination of raw potato starch and the probiotic had a beneficial effect on piglet growth performance and resulted in a reduction of diarrhea and increased microbial diversity in the gut. We conclude that the use of E. coli probiotic strains against E. coli K88 in the presence of raw potato starch is effective in reducing the negative effects of ETEC in a piglet challenge model.

Effect of inorganic ions on bud cell formation by Fusarium oxysporum in potato dextrose broth

Potato dextrose broth (PDB), a well-known medium for cultivation of fungi, can be made from potato extract and glucose (handmade PDB) or bought as a commercial powder (commercial PDB). Previously, we reported that bud cell formation and fungal biomass of Fusarium oxysporum in handmade PDB are higher than in commercial PDB, and the presence of high molecular weight (>20 MDa) carbohydrates in PDB promoted bud cell formation by most strains of F. oxysporum. In this study, we report the effects of inorganic ions in PDB on bud cell formation and fungal biomass production by F. oxysporum. Concentrations of Mg, K, Fe, PO4 3− and SO4 2− were higher and of Na and Cl− were lower in handmade PDB than in commercial PDB. Adding each inorganic ion alone to commercial PDB showed that Mg is critical for enhancement of bud cell formation by some strains of F. oxysporum. The addition of Mg2+ with raw potato starch to commercial PDB promoted bud cell formation by some, but not all, of the seven F. oxysporum strains tested in this study.

The effects of method of castration, rearing condition and diet on sensory quality of pork assessed by a trained panel

Beside surgical castration possible alternatives helping to reduce the incidence of boar taint in cooked pork are rearing conditions, immunocastration and feeding strategies for entire males known to lower the skatole levels. The goal of this study was to assess the effects of these alternatives on the sensory acceptability of pork. In experiment 1, carcasses from barrows, entire males (EM) and entire males fed raw potato starch (EM+) 7d before slaughter were selected based on the androstenone (<or=2 microg/g) and skatole (<or=0.32 microg/g) levels. In experiment 2, carcasses from barrows, immunocastrates (IC), entire males either group-penned (EMG) or individually penned (EMP) were selected based on the aforementioned criteria. Boar odour and boar flavour intensities of longissimus dorsi (LD) and neck chops were evaluated by trained panellists. Boar odour and flavour scores were higher (P<0.01) in neck than LD chops. Although skatole tissue levels in barrows and EM+ were similar (P>0.05), boar odour and flavour scores were greater (P<0.05) in EM+ than barrows. In experiment 2, scores for boar odour and flavour were lower (P<0.05) in pork from barrows and IC than EMP, with intermediate values for EMG. In conclusion, we observed a discrepancy between the known boar taint compounds androstenone and skatole and sensory acceptability, which indicates that other factors influenced the perception of boar taint. Thus, surgical castration with or without anesthesia or immunocastration are still the safest methods to avoid boar taint.

Effect of high molecular weight carbohydrates on bud cell formation by Fusarium oxysporum in potato dextrose broth

Potato dextrose broth (PDB), one of the most popular culture media for fungi, can be made in the laboratory from potato extract and glucose (handmade PDB) and also bought as powder (commercial PDB). We compared growth of Fusarium oxysporum in handmade and commercial PDBs. For seven strains tested, bud cell formation and fungal biomass were higher in handmade PDB than in commercial PDB. Gel filtration analyses revealed that handmade PDB contained carbohydrates with molecular weights >20 MDa, while most carbohydrates in commercial PDB were 20 MDa and enhanced bud cell formation by five of seven strains when added to commercial PDB. The addition of glucose to commercial PDB promoted biomass production but not bud cell formation. Furthermore, in a semisynthetic medium containing raw potato starch, bud cell formation was enhanced for all strains tested. These results indicate that the high molecular carbohydrates present in raw potatoes enhanced bud cell formation by Fusarium oxysporum.

Absence of an effect of dietary fibre or clinoptilolite on boar taint in entire male pigs fed practical diets

This study aimed to evaluate the possibility of reducing boar taint in boars (Piétrain × Hybrid) by addition of different feed ingredients (raw potato starch (RPS) 10%, raw potato starch 10% + wheat bran 5% (RPS + WB), lupins 10%, inulin 5%, clinoptilolite 1%) to a standard diet over a period of 4–6 weeks before slaughter. Control boars (CBOAR) as well as barrows were fed the standard diet. Efficacy of the different feed ingredients was evaluated by different boar taint detection methods: hot iron method, consumer panel, expert panel and laboratory analysis. According to all detection methods, clear differences were noticeable between boars and barrows. No differences in boar taint incidence were found between the boars on the different dietary treatments as assessed by consumers, experts, hot iron method or the concentration of skatole in fat. A significant effect on indole level was found, but no further differentiation could be made. The concentration of backfat androstenone was significantly higher for the inulin and control boar group compared to the lupin group. In conclusion, none of the feeding strategies tested in this study reduced boar taint in boars at the given percentages.

Immobilized bacterial α-amylase for effective hydrolysis of raw and soluble starch

Abstract The major concern in an enzymatic process is the instability of the enzyme under repetitive or prolonged use and inhibition by high substrate and product concentration. Immobilization is a very effective alternative in overcoming problems of instability and repetitive use of enzymes. Entrapment method of immobilization is advantageous over other methods as they do not involve chemical modification of the enzyme. α-Amylase produced by Bacillus amyloliquefaciens ATCC 23842 was immobilized in calcium alginate beads and used for the effective hydrolysis of soluble and raw potato starch which was comparable to the free enzyme. The levels of parameters (sodium alginate, calcium chloride and curing time) that significantly influence the immobilization of α-amylase in calcium alginate were analyzed and optimized using response surface methodology. Reactor studies were performed to study the reusability and operational stability of the beads. The alginate beads retained more than 60% of their initial efficiency after five batches of successive use and 40% of efficiency was exhibited in the 6th and 7th batch run of 6 h duration.

Raw potato starch in weaned pig diets and its influence on postweaning scours and the molecular microbial ecology of the digestive tract1

We evaluated the effect of raw potato starch (RPS) on growth performance, postweaning diarrhea, and gastrointestinal microbial populations in weaned piglets. Eighty-four piglets were weaned at 17 +/- 2 d of age with an average BW of 6.0 +/- 0.9 kg. Pigs were blocked by BW and assigned to 1 of 4 diets in a randomized complete block design with 7 replicate pens per diet and 3 pigs per pen. Treatments were 1) a positive control (PC) containing an antibiotic, 2) a negative control (NC) with no RPS and no antibiotic, 3) NC + 7% RPS (7% RPS), and 4) NC + 14% RPS (14% RPS). Diets were corn-wheat-soybean meal-based and formulated to meet NRC (1998) recommendations. The ADG, ADFI, and G:F ratio were determined weekly. Fecal consistency (FC) scoring was determined daily. After wk 3, 1 pig with a BW closest to the pen mean was killed to evaluate ileal and colonic mucosal-attached Escherichia coli and lactic acid bacteria, as well as digesta pH, VFA, and ammonia N concentrations. The DNA was extracted from ileum and colon digesta and used for molecular microbial evaluations using terminal-RFLP analysis of 16S rDNA genes. The ADG for wk 1 was greater (P < 0.01) for the PC diet, but diet had no effect on ADG during wk 3. The ADFI did not differ among treatments during the first 2 wk, and ADFI was least for 7% RPS diet during wk 3. The NC diet had a greater (P < 0.05) FC score during wk 1 than other treatments, but diet had no effect on FC score during wk 2 and 3. Diets had no effect on the colon lactic acid bacterial counts; however, the PC diet had decreased (P < 0.05) colon E. coli counts than other treatments. Ileum and colon digesta pH and total VFA concentrations did not differ among treatments. Pigs fed with 7 and 14% RPS diets had greater (P < 0.05) ileum ammonia N concentration compared with pigs fed with other diets. There was more diarrhea (P < 0.05) in the 14% than the 7% RPS and control treatments at d 21. This difference correlated with a decline (P < 0.05) in microbial diversity in the colon. We concluded that 7% RPS can be used to prevent postweaning diarrhea in weaned piglets, but there are no effects on growth performance.

Rheological properties of sweet potato starch before and after denaturalization

Based on the sweet potato starch, cationic starch, acetic starch and cationic-acetic compoundedly modified starch were made through chemical denaturalization. The above three kinds of static rheological parameter and dynamic rheological parameter were measured, respectively. The experimental result reveals that the thermal stability of starchy viscosity increases after chemical denaturalization. Under the condition of identical shearing rate, the shear stress of cationic-acetic ester compoundedly modified sweet potato starch paste is the largest among these kinds of sweet potato starch. This attributes to a phenomenon of shearing thinning. Furthermore, raw sweet potato starch has a larger gel intensity than that of modified starch.

Performances, meat quality and boar taint of castrates and entire male pigs fed a standard and a raw potato starch-enriched diet

In Europe there is increasing concern about the common practice of surgical castration of piglets without anaesthesia. One possible alternative to completely avoid castration is entire male pig production. Thus, the objective of the study was to compare the growth performance, carcass characteristics, organ weights, meat quality traits, fat score and boar taint compounds in the adipose tissue of group-penned entire male pigs and castrates. Furthermore, the effect of raw potato starch (RPS) fed for 7 days prior to slaughter was determined. Pigs (n = 36) were blocked by BW into 12 blocks (3 littermates/block) and assigned to three experimental groups: surgical castrates (C); entire males (EM); and entire males offered RPS (30 g RPS/100 g diet) for 7 days prior to slaughter (EM+). Pigs had ad libitum access to the feed from 22 to 107 kg, individual feed intake was recorded daily and BW once a week. Entire males grew slower (EM: 771, EM+: 776 v. C: 830 g/day; P < 0.01), consumed less feed (EM: 1.87, EM+: 1.89 v. C: 2.23 kg/day; P < 0.01) and were more efficient (feed conversion ratio: EM: 2.42, EM+: 2.44 v. C: 2.69 kg/kg; P < 0.01) than C. Compared to C, carcass dressing percentage was lower (EM: 79.4, EM+: 79.4 v. C: 81.6%; P < 0.01) and percentage of valuable cuts was higher (EM: 57.3, EM+: 56.5 v. 52.6%; P < 0.01) in entire males. The hearts (EM: 426, EM+: 425 v. C: 378 g), kidneys (EM: 387, EM+: 378 v. C: 311 g), bulbourethral (EM: 200, EM+: 195 v. C: 7 g) and salivary glands (EM: 99, EM+: 94 v. C: 42 g) were heavier (P < 0.001) in entire males than in C. Meat quality traits did not (P > 0.05) differ among experimental groups but the adipose tissue was more unsaturated in entire males than in C as indicated by the higher fat scores (EM: 69.1, EM+: 67.2 v. C: 63.6; P < 0.01). Feeding RPS reduced (P = 0.04) the skatole tissue concentrations (expressed in μg/g lipid) in EM+ (0.22) compared to EM (0.85), whereas androstenone and indole levels were not (P ⩾ 0.60) affected (EM: 1.7 and 0.10, EM+: 2.0 and 0.09, respectively). Although the current results confirmed the high efficiency of entire males compared to castrates, the observed high androstenone levels represent a major challenge to implement entire males production.

Long-term intake of resistant starch improves colonic mucosal integrity and reduces gut apoptosis and blood immune cells

Objective The potential effect of a long-term intake of resistant starch on colonic fermentation and on gut morphologic and immunologic indices of interest in bowel conditions in humans was studied in pigs. Methods Sixteen growing pigs were meal fed for 14 wk on a diet containing a large amount of raw potato starch (RPS; resistant starch) or corn starch (CS; digestible starch). Effects were assessed in the colon from the physicochemical properties of digesta and in the intestinal morphology, including lymphocytic infiltration, apoptosis, and proliferation activities. Hematologic and blood leukocyte cell subsets analysis were performed. Results After 97 d, the digestive content from RPS pigs was heavier than for CS pigs, producing a hypertrophy of tunica muscularis ( P < 0.05). The proportion of butyrate was two-fold higher in proximal colon digesta in RPS pigs ( P < 0.05). RPS-fed pigs had reduced apoptosis in the crypts, lamina propria and lymphoid nodules in the colon, and ileal Peyer’s patches ( P < 0.05). Fermentation of RPS reduced indices associated with damage to epithelial cells, such as crypt cell proliferation and magnesium excretion, whereas mucin sulfuration was increased, which promotes epithelial protection. The numbers of intraepithelial T cells and of blood leukocytes, neutrophils, and lymphocytes, mainly T-helper lymphocytes, were reduced in RPS pigs ( P < 0.05). Conclusion Long-term intake of RPS induces pronounced changes in the colonic environment, reduces damage to colonocytes, and improves mucosal integrity, reducing colonic and systemic immune reactivity, for which health benefits in inflammatory conditions are likely to be associated.