Production and characterization of poly‐3‐hydroxybutyrate from biodiesel‐glycerol by Burkholderia cepacia ATCC 17759

Glycerol, a byproduct of the biodiesel industry, can be used by bacteria as an inexpensive carbon source for the production of value‐added biodegradable polyhydroxyalkanoates (PHAs). Burkholderia cepacia ATCC 17759 synthesized poly‐3‐hydroxybutyrate (PHB) from glycerol concentrations ranging from 3% to 9% (v/v). Increasing the glycerol concentration results in a gradual reduction of biomass, PHA yield, and molecular mass (M_n and M_w) of PHB. The molecular mass of PHB produced utilizing xylose as a carbon source is also decreased by the addition of glycerol as a secondary carbon source dependent on the time and concentration of the addition. ¹H‐NMR revealed that molecular masses decreased due to the esterification of glycerol with PHB resulting in chain termination (end‐capping). However, melting temperature and glass transition temperature of the end‐capped polymers showed no significant difference when compared to the xylose‐based PHB. The fermentation was successfully scaled up to 200 L for PHB production and the yield of dry biomass and PHB were 23.6 g/L and 7.4 g/L, respectively. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

Effect of fermented soya beans on diarrhoea and feed efficiency in weaned piglets

AIMS: To evaluate anti-diarrhoeal and growth enhancing properties of fermented soya beans in weaned piglets. METHODS AND RESULTS: In a first phase piglet diet, toasted full-fat soya beans (20%) were replaced with either cooked soya beans or Rhizopus microsporus or Bacillus subtilis fermented soya beans. The effect on the incidence, severity and duration of diarrhoea in enterotoxigenic Escherichia coli (ETEC)-challenged weaned piglets was determined (pen trial, 24 piglets per treatment). Severity of diarrhoea was significantly less on the diet with Rhizopus-fermented soya beans compared with the control diet containing toasted soya beans. Piglets fed fermented soya beans showed increased feed intake (13 and 12%), average daily weight gain (18 and 21%) and feed efficiency (3 and 8%) (for Rhizopus and Bacillus-fermented soya beans, respectively). However, in the treatment groups an unequal mortality and a potential unequal distribution of receptor-positive piglets were observed. CONCLUSIONS: Cooked and fermented soya beans could be beneficial in the control of diarrhoea in ETEC-challenged weaned piglets (particularly Rhizopus fermented) and significantly improved weight gain and feed intake (particularly Bacillus fermented). SIGNIFICANCE AND IMPACT OF THE STUDY: Fermented soya beans could offer benefits with respect to the control of diarrhoea and feed efficiency in piglets.     

The potential effects of antioxidant feed additives in mitigating the adverse effects of corn naturally contaminated with <Emphasis Type="Italic">Fusarium</Emphasis> mycotoxins on antioxidant systems in the intestinal mucosa,plasma, and liver in weaned pigs

Seventy-two piglets (6.0 kg BW) were randomly distributed within six different dietary treatments to evaluate the effect of deoxynivalenol (DON) and the potential of four antioxidant feed additives in mitigating the adverse effects of DON on growth performances and oxidative status. Dietary treatments were as follows: control diet 0.8 mg/kg DON; contaminated diet (DON-contaminated diet) 3.1 mg/kg DON; and four contaminated diets, each supplemented with a different antioxidant feed additive, DON + vitamins, DON + organic selenium (Se)/glutathione (GSH), DON + quercetin, and DON + COMB (vitamins + Se/GSH + quercetin from the other treatments). Although DON was the main mycotoxin in the contaminated diet, this diet also contained 1.8 mg/kg of zearalenone (ZEN). The “mycotoxin” effects therefore included the combined effect of these two mycotoxins, DON, and ZEN. The DON-ZEN ingestion did not affect growth performances, average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F ratio), but partially induced oxidative stress in weaned pigs as shown by increased malondialdehyde (MDA) content in the plasma and superoxide dismutase (SOD) activity in liver (P?<?0.05). However, no change in the activity of other antioxidant enzymes or GSH concentrations was observed in plasma and liver of piglets fed the DON-contaminated diet (P?>?0.05). Supplementation with individual antioxidant feed additive had a limited effect in weaned pigs fed DON-ZEN-contaminated diets. Combination of antioxidants (vitamins A, C, and E, quercetin, and organic Se/GSH) reduced plasma and liver MDA content and SOD activity in liver (P?<?0.05) of piglets fed DON-ZEN-contaminated diets. Furthermore, this combination also reduced MDA content in the ileum (P?<?0.05), although activity of glutathione peroxidases (GPx), SOD or catalase (CAT) in the ileum was not affected by DON-ZEN contamination or antioxidant supplements. In conclusion, DON-ZEN contamination induced oxidative stress in weaned pigs and combination of antioxidant feed additives restored partially the oxidative status. Further studies will be necessary to assess whether the effects of antioxidant feed additives on oxidative status are specific when feed is contaminated with DON-ZEN.     

Response of performance characteristics and fecal consistency to long-lasting dietary supplementation with the probiotic strain Bacillus cereus var. toyoi to sows and piglets

As part of an interdisciplinary research project, we studied the performance response of sows and their litters to the probiotic strain Bacillus cereus var. toyoi as well as feces consistency of piglets. Gestating sows (n=26) were randomly allotted into two groups. The probiotic B. cereus var. toyoi was administered by dietary supplementation to one group of sows and their respective litters (probiotic group) whereas the second group (control group) received no probiotic supplementation. The duration of the application was nearly 17 weeks for sows (day 90 ante partum until day 28 post partum) and six weeks for piglets (day 15-56). Piglets were weaned after 28 days. Body weight and feed consumption were recorded weekly and fecal consistency of weaned piglets was studied daily. B. cereus var. toyoi was recovered from feces of sows and piglets as well as from digesta of piglets in the probiotic group, while being absent from all samples of control animals. In addition, the probiotic was detected in piglet feces and digesta before pre-starter feed was offered, indicating a second route of uptake besides diet. Sows of the probiotic group nursed numerically more piglets and supported a higher sum of total nursing days of all piglets within each litter than control sows (p = 0.04). In turn, body weight (BW) up to day 35 was greater for control piglets (p < 0.01), while average daily gain and gain to feed ratio (G:F) in weeks six and eight postweaning was higher in the probiotic group (p < 0.05). The overall G:F of the total postweaning period was 680 g/kg and 628 g/kg in the probiotic group and control group, respectively (p = 0.009). During the trial a high prevalence of liquid feces with its maximum in the second week after weaning was observed. Probiotic supplementation led to a reduction in the incidence of liquid feces and postweaning diarrhea by 38% and 59%, respectively (p < 0.001).     

Marine ash‐products influence growth and feed utilization when Atlantic cod Gadus morhua L. are fed plant‐based diets

Atlantic cod Gadus morhua L. were fed high plant protein diets added to either shrimp‐shell meal or crab‐shell meal. The aims were to investigate if diluting dietary energy would reduce the liver index (HSI) and if marine ash would add value to plant protein‐based diets. Two control diets were used: a high plant protein control diet (PP) with no marine ash addition, and a fishmeal‐based diet (FM) with no marine ash addition. All diets were evaluated in small cod (initial weight 79 ± 15g) and in market‐size cod (initial weight 1579 ± 20 g). Addition of crab‐shell meal up to 20% and shrimp‐shell meal up to 10% did not influence liver size in either small or market‐size cod. An addition of up to 20% crab‐shell meal and 10% shrimp‐shell meal improved growth compared to the PP control diet, and stimulated increased feed intake. However, 10% shrimp‐shell meal and 20% crab‐shell meal diets resulted in a similar intake of energy and protein as the control groups. Increasing shrimp‐shell meal to 20% resulted in reductions in feed intake, fat digestibility and growth, and in altered gut histology. All diets, except the 20% shrimp added diet, resulted in normal ranges of plasma nutrients and blood hematological values, showing good fish health with or without the marine ash addition.     

Resorption und Einbau radioaktiv markierter Aminosäuren bei Verabreichung unterschiedlicher Proteinträger an Ratten

Since the announcement of the ban on the use of antibiotics as antimicrobial growth promoters in the feed of pigs in 2006 the investigation towards alternative feed additives has augmented considerably. Although fermented liquid feed is not an additive, but a feeding strategy, the experimental work examining its possible advantages also saw a rise. The use of fermented liquid feed (FLF) has two main advantages, namely that the simultaneous provision of feed and water may result in an alleviation of the transition from the sow milk to solid feed and may also reduce the time spent to find both sources of nutrients, and secondly, that offering FLF with a low pH may strengthen the potential of the stomach as a first line of defence against possible pathogenic infections. Because of these two advantages, FLF is often stated as an ideal feed for weaned piglets. The results obtained so far are rather variable, but in general they show a better body weight gain and worse feed/gain ratio for the piglets. However, for growing-finishing pigs on average a better feed/gain ratio is found compared to pigs fed dry feed. This better performance is mostly associated with less harmful microbiota and better gut morphology. This review provides an overview of the current knowledge of FLF for pigs, dealing with the FLF itself as well as its effect on the gastrointestinal tract and animal performance.     

大豆寡糖对断奶环江香猪生长性能和营养物质代谢的影响

为了探讨大豆寡糖(SBOS)作为抗生素替代物对断奶仔猪生长性能的影响及其作用机制,饲养试验选用21日龄断奶的环江香猪12头,随机分为2组,每组6头,分别饲喂添加0.5%SBOS日粮和抗生素对照日粮,试验期为14 d。记录每天的采食量,分别于试验开始和结束时称取空腹体重并采集血液,肝素抗凝离心分离血浆,测定生化参数和游离氨基酸水平。消化试验选用10头环江香猪,随机分为2组,处理同饲养试验。预试期4 d,正试期3 d,收集粪样,指示剂法测定干物质、粗蛋白和粗脂肪的消化率。结果表明,与抗生素对照组相比,SBOS组仔猪平均日采食量、日增重和料重比均无显著变化;血浆尿素氮和血氨含量显著下降,总蛋白含量显著升高(P<0.05);血浆甘氨酸、组氨酸、赖氨酸、精氨酸和蛋氨酸的含量均显著升高(P<0.05);粗蛋白和粗脂肪消化率有提高趋势。提示SBOS可替代抗生素用于断奶仔猪日粮。     

Production of high levels of poly‐3‐hydroxybutyrate in plastids of Camelina sativa seeds

Poly‐3‐hydroxybutyrate (PHB) production in plastids of Camelina sativa seeds was investigated by comparing levels of polymer produced upon transformation of plants with five different binary vectors containing combinations of five seed‐specific promoters for expression of transgenes. Genes encoding PHB biosynthetic enzymes were modified at the N‐terminus to encode a plastid targeting signal. PHB levels of up to 15% of the mature seed weight were measured in single sacrificed T₁ seeds with a genetic construct containing the oleosin and glycinin promoters. A more detailed analysis of the PHB production potential of two of the best performing binary vectors in a Camelina line bred for larger seed size yielded lines containing up to 15% polymer in mature T₂ seeds. Transmission electron microscopy showed the presence of distinct granules of PHB in the seeds. PHB production had varying effects on germination, emergence and survival of seedlings. Once true leaves formed, plants grew normally and were able to set seeds. PHB synthesis lowered the total oil but not the protein content of engineered seeds. A change in the oil fatty acid profile was also observed. High molecular weight polymer was produced with weight‐averaged molecular weights varying between 600 000 and 1 500 000, depending on the line. Select lines were advanced to later generations yielding a line with 13.7% PHB in T₄ seeds. The levels of polymer produced in this study are the highest reported to date in a seed and are an important step forward for commercializing an oilseed‐based platform for PHB production.     

Fermented liquid feed for pigs

Since the announcement of the ban on the use of antibiotics as antimicrobial growth promoters in the feed of pigs in 2006 the investigation towards alternative feed additives has augmented considerably. Although fermented liquid feed is not an additive, but a feeding strategy, the experimental work examining its possible advantages also saw a rise. The use of fermented liquid feed (FLF) has two main advantages, namely that the simultaneous provision of feed and water may result in an alleviation of the transition from the sow milk to solid feed and may also reduce the time spent to find both sources of nutrients, and secondly, that offering FLF with a low pH may strengthen the potential of the stomach as a first line of defence against possible pathogenic infections. Because of these two advantages, FLF is often stated as an ideal feed for weaned piglets. The results obtained so far are rather variable, but in general they show a better body weight gain and worse feed/gain ratio for the piglets. However, for growing-finishing pigs on average a better feed/gain ratio is found compared to pigs fed dry feed. This better performance is mostly associated with less harmful microbiota and better gut morphology. This review provides an overview of the current knowledge of FLF for pigs,dealing with the FLF itself as well as its effect on the gastrointestinal tract and animal performance.     

Toxicity of bryostatin‐1 on the embryo‐fetal development of Sprague‐Dawley rats

BACKGROUND: Bryostatin‐1, a highly oxygenated marine macrolide with a unique polyacetate backbone isolated from the marine animal Bugula neritina (Linnaeus), is now being developed as an anti‐cancer drug for treating malignancy. In the present study, developmental toxicity of bryostatin‐1 was evaluated in Sprague–Dawley rats. METHODS: Bryostatin‐1 was intravenously administered to rats on gestation days 6–15 at 4.0, 8.0, and 16.0 µg/kg on a daily basis. Then the reproductive parameters were determined in animals, and fetuses were examined for external, visceral, and skeletal malformations. RESULTS: The total weight gains were significantly different in animals between the control group and 8.0 and 16.0 µg/kg bryostatin‐1 groups during and after treatment. The resorption and death fetus rates were significantly different between the bryostatin‐1 group (16 µg/kg) and the control group. The fetal weight and fetal crown‐rump length in the bryostatin‐1 groups were significantly lower than that in the control group. CONCLUSIONS: Our results indicated that maternal toxicity occurred when the dose of bryostatin‐1 was at 8.0 µg/kg, embryotoxicity at 16.0 µg/kg, and fetotoxicity at 4.0 µg/kg; but bryostatin‐1 showed no teratogenic effect in rats. In light of our findings, bryostatin‐1 should be used with caution in pregnant women with cancer, if they would like to continue the pregnancy. Birth Defects Res (Part B) 89:171–174, 2010. © 2010 Wiley‐Liss, Inc.     

Effects of weaning age and formic acid-based feed additives on pigs from weaning to slaughter

Two hundred and forty piglets were used in a 2 x 6 factorial experiment to study the effects of weaning age (26 or 36 d) and four formic acid-based feed additives on the performance of pigs from weaning to slaughter. Either formic acid (F) or a mixture of formic acid, propionic acid, and potassium sorbate (FPS) or a mixture of formic acid, propionic acid, and sodium benzoate (FPB) or formic acid in a diatomaceous earth carrier (FD) were added to the diets of weaned piglets (from weaning to 60 d of age) and growing (18-46 kg) and finishing pigs (46-107 kg) to provide 8, 6, and 6 g acid per kg feed, respectively. The negative control treatment's (C) diets contained no growth promoters, whereas the positive control treatment's weaner and grower diets were supplemented with 40 mg/kg of avilamycin (A). The piglets weaned at the age of 26 and 36 d weighed 7.6 and 10.7 kg at weaning (p < 0.001), and 18.5 and 17.9 kg at the age of 60 d (p > 0.05), respectively. There was a weaning age x feed additive interaction in the weight gain of piglets after weaning (p < 0.05). The weight gain of piglets weaned on day 26 was enhanced by A, FPS, and FD (p < 0.05), and that of piglets weaned on day 36 by A and FPB (p < 0.05). The feed conversion ratio was not affected by weaning ages but was decreased in groups A, F, FBS, and FPB (p < 0.05). The severity of post-weaning diarrhoea was less in groups A, F, FPS, and FD than in C (p < 0.05). In piglets weaned on day 26, faecal water content and the total Escherichia coli count were highest 9 d after weaning. The total E. coli count was reduced only by FD (p < 0.05). Increased faecal water content was characterized by increased faecal Na+ and decreased K+ concentrations. Weaning age did not influence performance or carcass quality in the growing-finishing pigs. Feed additives did not affect weight gain in the growing pigs, but FPS and FPB enhanced weight gain during finishing period and total fattening (p < 0.05). In summary, the pigs' growth performance from weaning to slaughter was not affected by weaning age but it was enhanced by mixtures of formic and propionic acids with small amounts of sorbate or benzoate.     

Fütterungseinfluss von Deoxynivalenol-belastetem Weizen bei Ferkeln

Effects of the mycotoxin deoxnivalenol (DON) on weaned piglets were investigated. Two feeding trials were conducted with naturally contaminated wheat in the ration. In the first trial as preliminary study weaned piglets were fed for one week with 7.7 mg DON per kg ration, intake of DON contaminated diets was not associated with any obvious negative health effects. Also in the main feeding trial with 3 mg DON per kg ration no vomiting and other negative clinical symptoms could be registered. The feed intake and the daily weight gains were significantly lower in the DON fed group when compared with control group, but the feed conversion rates were slightly improved in group fed DON.

Presented at the 25^th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003     

The use of an acetoacetyl‐CoA synthase in place of a β‐ketothiolase enhances poly‐3‐hydroxybutyrate production in sugarcane mesophyll cells

Engineering the production of polyhydroxyalkanoates (PHAs) into high biomass bioenergy crops has the potential to provide a sustainable supply of bioplastics and energy from a single plant feedstock. One of the major challenges in engineering C₄ plants for the production of poly[(R)‐3‐hydroxybutyrate] (PHB) is the significantly lower level of polymer produced in the chloroplasts of mesophyll (M) cells compared to bundle sheath (BS) cells, thereby limiting the full PHB yield‐potential of the plant. In this study, we provide evidence that the access to substrate for PHB synthesis may limit polymer production in M chloroplasts. Production of PHB in M cells of sugarcane is significantly increased by replacing β‐ketothiolase, the first enzyme in the bacterial PHA pathway, with acetoacetyl‐CoA synthase. This novel pathway enabled the production of PHB reaching an average of 6.3% of the dry weight of total leaf biomass, with levels ranging from 3.6 to 11.8% of the dry weight (DW) of individual leaves. These yields are more than twice the level reported in PHB‐producing sugarcane containing the β‐ketothiolase and illustrate the importance of producing polymer in mesophyll plastids to maximize yield. The molecular weight of the polymer produced was greater than 2 × 10⁶ Da. These results are a major step forward in engineering a high biomass C₄ grass for the commercial production of PHB.     

Effective recovery of poly‐β‐hydroxybutyrate (PHB) biopolymer from Cupriavidus necator using a novel and environmentally friendly solvent system

This work demonstrates a significant advance in bioprocessing for a high‐melting lipid polymer. A novel and environmental friendly solvent mixture, acetone/ethanol/propylene carbonate (A/E/P, 1:1:1 v/v/v) was identified for extracting poly‐hydroxybutyrate (PHB), a high‐value biopolymer, from Cupriavidus necator. A set of solubility curves of PHB in various solvents was established. PHB recovery of 85% and purity of 92% were obtained from defatted dry biomass (DDB) using A/E/P. This solvent mixture is compatible with water, and from non‐defatted wet biomass, PHB recovery of 83% and purity of 90% were achieved. Water and hexane were evaluated as anti‐solvents to assist PHB precipitation, and hexane improved recovery of PHB from biomass to 92% and the purity to 93%. A scale‐up extraction and separation reactor was designed, built and successfully tested. Properties of PHB recovered were not significantly affected by the extraction solvent and conditions, as shown by average molecular weight (1.4 × 10⁶) and melting point (175.2°C) not being different from PHB extracted using chloroform. Therefore, this biorenewable solvent system was effective and versatile for extracting PHB biopolymers. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:678–685, 2016     

复合活菌制剂对断奶仔猪生长性能及血清溶菌酶含量的影响

目的观察复合活菌制剂对断奶仔猪生长性能及血清溶菌酶含量的影响。方法选择长白二元杂交断奶仔猪90头进行实验,断奶日龄为35 d。共分为5个组,每组设3个重复,每个重复随机选取健康仔猪6头。实验组一:饲喂基础日粮+0.1%复合制剂(纳豆杆菌,双歧杆菌,罗伊乳杆菌),实验组二:饲喂基础日粮+0.1%复合制剂(纳豆杆菌,双歧杆菌,干酪乳杆菌),实验组三:饲喂基础日粮+0.1%复合制剂(纳豆杆菌,双歧杆菌,嗜酸乳杆菌),实验组四:饲喂基础日粮+0.1%复合制剂(纳豆杆菌,双歧杆菌,罗伊乳杆菌,干酪乳杆菌,嗜酸乳杆菌),对照组:饲喂基础日粮。其中复合制剂中益生菌活菌数为109CFU/g。饲养30 d后观察复合活菌制剂对断奶仔猪生长性能及血清溶菌酶含量的影响。结果在日增重、饲料效率及血清溶菌酶方面,实验组一和二显著高于对照组(P0.05);在腹泻率方面,实验组均显著低于对照组(P0.05)。结论在仔猪日粮中添加复合活菌制剂可提高每头断奶仔猪平均日增重及饲料效率,降低腹泻的发病率,且增高仔猪血清溶菌酶含量,提高仔猪的免疫机能,从而提高经济效益。     

Response of performance characteristics and fecal consistency to long-lasting dietary supplementation with the probiotic strain Bacillus cereus var. toyoi to sows and piglets

Abstract

As part of an interdisciplinary research project, we studied the performance response of sows and their litters to the probiotic strain Bacillus cereus var. toyoi as well as feces consistency of piglets. Gestating sows (n = 26) were randomly allotted into two groups. The probiotic B. cereus var. toyoi was administered by dietary supplementation to one group of sows and their respective litters (probiotic group) whereas the second group (control group) received no probiotic supplementation. The duration of the application was nearly 17 weeks for sows (day 90 ante partum until day 28 post partum) and six weeks for piglets (day 15–56). Piglets were weaned after 28 days. Body weight and feed consumption were recorded weekly and fecal consistency of weaned piglets was studied daily. B. cereus var. toyoi was recovered from feces of sows and piglets as well as from digesta of piglets in the probiotic group, while being absent from all samples of control animals. In addition, the probiotic was detected in piglet feces and digesta before pre-starter feed was offered, indicating a second route of uptake besides diet. Sows of the probiotic group nursed numerically more piglets and supported a higher sum of total nursing days of all piglets within each litter than control sows (p = 0.04). In turn, body weight (BW) up to day 35 was greater for control piglets (p < 0.01), while average daily gain and gain to feed ratio (G:F) in weeks six and eight postweaning was higher in the probiotic group (p < 0.05). The overall G:F of the total postweaning period was 680 g/kg and 628 g/kg in the probiotic group and control group, respectively (p = 0.009). During the trial a high prevalence of liquid feces with its maximum in the second week after weaning was observed. Probiotic supplementation led to a reduction in the incidence of liquid feces and postweaning diarrhea by 38% and 59%, respectively (p < 0.001).     

Enhanced phytase production from Achromobacter sp. PB‐01 using wheat bran as substrate: Prospective application for animal feed

This article deals with the optimization of the various parameters for production of phytase using Achromobacter sp. PB‐01 in submerged fermentation (SmF). A semisynthetic medium containing ingredients of phytase screening media (PSM) supplemented with 2% (w/v) sucrose, 1% (w/v) peptone, and 10% (w/v) wheat bran was found to be the best production medium among the various combinations tried. Among various surfactants added to SmF, Triton X‐100 (0.1%) exhibited a 16% increase in phytase activity. An overall 11.2 fold enhancement in enzyme activity (0.79 U/mL→8.84 U/mL) was attained when SmF was carried out using 0.5% (v/v) inoculum of a 15 h old culture of Achromobacter sp. PB‐01 at an initial pH of 5.5, temperature 30°C and allowed to grow for 48 h. Presence of accessory hydrolytic enzymes in the crude extract further added value as feed additive by mediating efficient degradation of non‐starch polysaccharides (NSP). In addition, we also investigated the efficacy of phytase on different agro‐industrial residues using in vitro experiments that simulated the conditions of the digestive tract. Results indicate that phytase from our source hydrolyze phytate efficiently with the concomitant liberation of inorganic phosphate, protein, reducing sugar, and calcium. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

Dietary self-selection for organic acids by the piglet

Two feeding trials using 48 weaned crossbred piglets each were carried out to determine the effect of acidifying diets with potassium diformate (K-diformate), formic or sorbic acid on dietary preferences in piglets. In Exp. 1 two reference groups were fed either an unacidified diet or a diet containing 2.4% of K-diformate with no choice for selection. Furthermore, piglets in choice group 1 and 2 had the choice between an unacidified diet and a diet supplemented with 1.2 and 2.4% K-diformate, respectively. In Exp. 2, animals of three reference groups received exclusively an unacidified diet or diets supplemented with 1.2% formic acid or 1.2% sorbic acid, respectively. The animals of the choice groups had the choice between an unacidified diet and diets with 1.2% formic acid or 1.2% sorbic acid, respectively. In Exp. 1 average daily feed intake, daily gain and feed conversion ratio were 751?g, 458?g and 1.64?kg/kg, respectively, with no significant differences between treatments. In both choice feeding groups animals chose the diets on offer at random (each around 50%). In Exp. 2 growth and feed intake were not affected by the treatment, but feed conversion ratio was enhanced due to the 1.2% formic acid supplementation. Animals of both organic acid choice groups showed a significant preference for the unacidified diets in each experimental week. The formic acid and sorbic acid diets represented on average only 13.5% and 23.5% of the total feed intake. The present results demonstrate that the inclusion of 1.2% sorbic or formic acid or 2.4% of K-diformate in piglet diets has no negative impact on feed intake, but in a situation of choice feeding, piglets will refuse diets acidified with 1.2% formic or sorbic acid, presumably because of negative taste cues. Acidifying the diets with varying amounts of a K-diformate had no effect on dietary preferences of piglets.     

Response of piglets weaned from sows fed diets supplemented with conjugated linoleic acid (CLA) to an Escherichia coli K88+ oral challenge

Seventy-eight Cotswold piglets weaned from sows receiving 0% or 2% conjugated linoleic acid (CLA)-supplemented rations from day 85 of gestation through lactation were allocated to nursery diets (ND) according to their dam's lactation ration (LR) as follows (1) 0%-0% (0% CLA LR: 0% CLA ND, n = 17); (2) 0%-2% (0% CLA LR: 2% CLA ND, n = 17); (3) 2%-0% (2% CLA LR: 0% CLA ND, n = 23); and (4) 2%-2% (2% CLA LR: 2% CLA ND, n = 21). At 28 ± 2 days of age all piglets received an oral Escherichia coli K88+ (enterotoxigenic Escherichia coli, ETEC) challenge and were subsequently monitored for scour development and overall health until 36 ± 2 days of age, after which blood and tissue samples were collected. Piglet BW was not affected by dietary CLA supplementation to LR (P > 0.05). However, by day 36 piglets receiving 2% CLA-supplemented ND were significantly lighter (P < 0.05) than piglets receiving control diets. Average daily gain and feed efficiency were not affected by CLA supplementation. Average daily feed intake (ADFI) was greater for piglets weaned from 2% CLA-supplemented sows from day 17 to 28 (P < 0.05), otherwise ADFI was unaffected by dietary CLA supplementation (P > 0.05). The development of scours was less severe in piglets weaned from 2% CLA-supplemented sows at 8, 24, 48 and 56 h after ETEC challenge (P < 0.05). Intestinal coliform and lactic acid bacteria populations post challenge were not affected by CLA supplementation. However, cecal ammonia-N was numerically greatest in 0%-0% piglets compared to the other treatment groups, and the total volatile fatty acid production was numerically lower in 0%-0% and 0%-2% piglets compared to 2%-0% and 2%-2% piglets. In addition, piglets weaned from 2% CLA-supplemented sows had increased serum immunoglobulin A (P < 0.001) and G (P < 0.05) levels and reduced (P < 0.05) intestinal mucosal inflammation compared to piglets weaned from control sows. Although there were no obvious additional health effects observed when CLA was provided in ND, supplementing sow rations with 2% CLA from mid-gestation through weaning appears to have immune-stimulating carry-over effects post weaning. Thus, supplementing sow rations with CLA may be a practical strategy for enhancing passive immune transfer and improving the immune status and overall gut health of nursery piglets.     

Dietary self-selection for organic acids by the piglet

Two feeding trials using 48 weaned crossbred piglets each were carried out to determine the effect of acidifying diets with potassium diformate (K-diformate), formic or sorbic acid on dietary preferences in piglets. In Exp. 1 two reference groups were fed either an unacidified diet or a diet containing 2.4% of K-diformate with no choice for selection. Furthermore, piglets in choice group 1 and 2 had the choice between an unacidified diet and a diet supplemented with 1.2 and 2.4% K-diformate, respectively. In Exp. 2, animals of three reference groups received exclusively an unacidified diet or diets supplemented with 1.2% formic acid or 1.2% sorbic acid, respectively. The animals of the choice groups had the choice between an unacidified diet and diets with 1.2% formic acid or 1.2% sorbic acid, respectively. In Exp. 1 average daily feed intake, daily gain and feed conversion ratio were 751 g, 458 g and 1.64 kg/kg, respectively, with no significant differences between treatments. In both choice feeding groups animals chose the diets on offer at random (each around 50%). In Exp. 2 growth and feed intake were not affected by the treatment, but feed conversion ratio was enhanced due to the 1.2% formic acid supplementation. Animals of both organic acid choice groups showed a significant preference for the unacidified diets in each experimental week. The formic acid and sorbic acid diets represented on average only 13.5% and 23.5% of the total feed intake. The present results demonstrate that the inclusion of 1.2% sorbic or formic acid or 2.4% of K-diformate in piglet diets has no negative impact on feed intake, but in a situation of choice feeding, piglets will refuse diets acidified with 1.2% formic or sorbic acid, presumably because of negative taste cues. Acidifying the diets with varying amounts of a K-diformate had no effect on dietary preferences of piglets.