Antibiotics in the aquatic environment - A review - Part II

Prebiotics are non-digestible (by the host) food ingredients that have a beneficial effect through their selective metabolism in the intestinal tract. Key to this is the specificity of microbial changes. The present paper reviews the concept in terms of three criteria: (a) resistance to gastric acidity, hydrolysis by mammalian enzymes and gastrointestinal absorption; (b) fermentation by intestinal microflora; (c) selective stimulation of the growth and/or activity of intestinal bacteria associated with health and wellbeing. The conclusion is that prebiotics that currently fulfil these three criteria are fructo-oligosaccharides, galacto-oligosaccharides and lactulose, although promise does exist with several other dietary carbohydrates. Given the range of food vehicles that may be fortified by prebiotics, their ability to confer positive microflora changes and the health aspects that may accrue, it is important that robust technologies to assay functionality are used. This would include a molecular-based approach to determine flora changes. The future use of prebiotics may allow species-level changes in the microbiota, an extrapolation into genera other than the bifidobacteria and lactobacilli, and allow preferential use in disease-prone areas of the body.

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Dietary modulation of the human colonic microbiota: updating the concept of prebiotics

It has become increasingly clear that life-history patterns among the vertebrates have been shaped by the plethora and variety of immunological risks associated with parasitic faunas in their environments. Immunological competence could very well be the most important determinant of life-time reproductive success and fitness for many species. It is generally assumed by evolutionary ecologists that providing immunological defences to minimise such risks to the host is costly in terms of necessitating trade-offs with other nutrient-demanding processes such as growth, reproduction, and thermoregulation. Studies devoted to providing assessments of such costs and how they may force evolutionary trade-offs among life-history characters are few, especially for wild vertebrate species, and their results are widely scattered throughout the literature. In this paper we attempt to review this literature to obtain a better understanding of energetic and nutritional costs for maintaining a normal immune system and examine how costly it might be for a host who is forced to up-regulate its immunological defence mechanisms. The significance of these various costs to ecology and life history trade-offs among the vertebrates is explored. It is concluded that sufficient evidence exists to support the primary assumption that immunological defences are costly to the vertebrate host.

https://www.jstor.org/stable/pdfplus/3546398.pdf

Trade‐offs in evolutionary immunology: just what is the cost of immunity?

Preface * Fatty acids and fertility in dairy cows * Environmental and genetic influences on successful heifer rearing * Reducing dietary phosphorus inputs within dairy systems * Practical aspects of feeding grass to dairy cows * Practical considerations of feed evaluation systems for dairy cows * Adapting livestock production systems to climate change * Legislation affecting animal production systems * Mycotoxin issues in farm animals and strategies to reduce mycotoxins in animal feeds * The effect of nutrition on stress and immunity * Potential applications of GM technology * Influence of feed processing technology on pig performance * Piglet starter feeding in a changing business environment * Organic acids in pig diets * Amino acid requirements in piglets with special emphasis on tryptophan and valine * Factors affecting pork quality * List of participants * Index

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Recent Advances in Animal Nutrition

Altering the Intestinal Microbiota during a Critical Developmental Window Has Lasting Metabolic Consequences

Antibiotics were discovered over 50 years ago and have since been widely used in the livestock and poultry industries. They represent an extremely important tool in the efficient production of pork, beef, poultry meat, and other animal products. When used at low (subtherapeutic) levels in feeds, antibiotics improve growth rate and efficiency of feed utilization, reduce mortality and morbidity, and improve reproductive performance. Antibiotics are also used at intermediate levels to prevent disease and at high (therapeutic) levels to treat diseases in animals.

Why and how antibiotics are used in swine production

The physical characteristics, chemical composition, and nutritional value of distillers dried grains with solubles (DDGS) from seven beverage alcohol and two fuel alcohol manufacturers were evaluated in studies with chicks and pigs. Color scores of the DDGS ranged from very light to very dark and odor scores ranged from normal to burnt or smoky. The DDGS ranged from 23.4 to 28.7% CP, 2.9 to 12.8% fat, 8.8 to 36.9% ADIN, 28.8 to 40.3% NDF, 10.3 to 18.1% ADF, and 3.4 to 7.3% ash. Lysine concentrations of the DDGS ranged from .43 to .89%. In the first experiment, 12 corn-based diets were fed to 1-d-old chicks for 21 d to assess the nutritional value of the DDGS sources. A low-protein basal diet was supplemented with soybean meal to provide 13.6, 16.5, or 19.0% CP or supplemented with 20% DDGS, which supplied approximately the same amount of CP as the highest level of soybean meal. Weight gain, feed intake, and feed/gain were influenced (P < .01) by source of DDGS. The weight gain of chicks fed the DDGS sources ranged from 85% of that chicks fed the highest level of soybean meal to less than that of chicks fed the low-protein basal diet. Blends of the three best sources of DDGS and the three poorest sources of DDGS were evaluated in a subsequent chick trial. The relative nutritional values of the two blends were similar to the average of the sources that made up the blends. Performance responses to various blends of DDGS in the pig experiment paralleled those of the chick trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Physical, chemical, and nutritional characteristics of distillers dried grains with solubles for chicks and pigs.

Brewers dried yeast, a source of mannan oligosaccharides (MOS), was assessed as an alternative to an antimicrobial agent (carbadox) for young pigs in two experiments. The yeast contained 5.2% MOS. Agglutination tests confirmed adsorption of several serovars of E. coli and Salmonella spp. onto the yeast product. In Exp. 1, seven replicates (five pigs per pen) of 22-d-old pigs were fed a nonmedicated basal diet or the basal diet with carbadox (55 mg/kg), yeast (3%), or a combination of 3% yeast and 2% citric acid for 28 d. Carbadox did not improve growth performance. Growth rate and feed intake were depressed (P 0.05) among treatments, but fecal shedding of carbadox-resistant coliforms was higher (P < 0.01) during the 9-d period in pigs fed carbadox. Total fecal coliforms were consistently lower throughout the postinoculation period in pigs fed yeast (P < 0.05). Yeast reduced colonization oftotal coliforms in the duodenum,jejunum, cecum, and colon, but it did not have a consistent effect on colonization of E. coli K88. Pigs fed yeast tended (P < 0.10) to have higher serum IgG levels than controls. In these experiments, brewers dried yeast and carbadox had minimal effects on growth, microbial populations, and intestinal health traits of early-weaned pigs, but certain serum immunological traits were enhanced by feeding yeast.

Brewers dried yeast as a source of mannan oligosaccharides for weanling pigs.

An experiment was conducted to determine the effect of high dietary intakes of Zn and Cu and their combination on growth performance of weanling pigs with diverse health status and management strategies. Twelve experiment stations cooperated and used a total of 1,356 pigs that averaged 6.55 kg BW and 22.2 d age at weaning. The four dietary treatments, all of which met or exceeded NRC requirements, were 1) control, 2) 3,000 ppm Zn (from Zn oxide), 3) 250 Cu ppm (from Cu sulfate), or 4) 3,000 ppm Zn and 250 ppm Cu. The diets were fed as a complex Phase I diet (1.4% lysine) for 7 d followed by a Phase II diet (1.2% lysine) for 21 d. Chlortetracycline (220 ppm) was added to all diets. Fecal color (1 = yellow to 5 = black) and consistency (1 = very firm to 5 = very watery) were scored daily for 3 wk. At the end of the 28-d study, 412 pigs were bled at five stations, and plasma Cu, Zn, and Fe concentrations were determined at one station with atomic absorption spectrophotometry. Average daily gain (375, 422, 409, 415 g/d), feed intake (637, 690, 671, 681 g/d), and gain/feed (586, 611, 611, 612 g/kg) were improved (P < .01) by the addition of Zn and(or) Cu. Significant Cu x Zn interactions imply that the responses to Zn and Cu were independent and not additive. There were significant (P < .01) Zn and Cu effects and a Zn x Cu interaction on fecal color (3.17, 3.24, 4.32, 3.57) and consistency (2.39, 2.14, 2.14, 2.13). Dietary additions of Cu and Zn resulted in elevated plasma concentrations of Cu and Zn, respectively. These data indicate that pharmacological additions of 3,000 ppm Zn (oxide) or 250 ppm Cu (sulfate) stimulate growth beyond that derived from intakes of Zn and Cu that meet nutrient requirements. However, the combination of Zn and Cu did not result in an additive growth response.

Growth promotion effects and plasma changes from feeding high dietary concentrations of zinc and copper to weanling pigs (regional study).

Four experiments involving 225 pigs were conducted to assess the efficacy of a microbial phytase (FINASE, Alko Ltd Biotechnology, Rajamaki, Finland) produced by Aspergillus niger in corn-soybean meal or dextrose-cornstarch-soybean meal-based diets In two experiments with growing-finishing pigs, fortified corn-soybean meal diets were formulated to be adequate (50%) or inadequate (40 or 30%) in P during the growing phase followed by adequate (40%) or inadequate (30%) P in the finishing phase Mono-dicalcium phosphate was the source of supplemental P Half the diets were supplemented with phytase (500 phytase units/g) Rate and efficiency of gain and bone breaking strength were decreased when P-deficient diets were fed Phytase supplementation of the low-P diets restored growth rate and feed:gain to levels that approached those of pigs fed the adequate-P control diet Bone strength was partially restored to that of the controls In two additional experiments, pigs were fed low-P basal diets in which all the dietary P came from soybean meal or a corn-soybean meal blend Both diets contained 05% available P Graded levels of monosodium phosphate were added to these diets, up to 15% added P, to establish a standard curve Phytase was added to the basal diet at 250, 500, or 1,000 units/g Growth rate and bone strength improved linearly (P < 01) with added monosodium phosphate and with increasing levels of supplemental phytase Based on estimates of total and available P intakes, the highest level of phytase (1,000 units/g) increased the bioavailability of the P from 25% in the soybean meal diet to 57% in the phytase-supplemented diet, and from 15% in the corn-soybean diet to 43% in the phytase-supplemented diet Expressed on the basis of the improvement in phytate P availability, this level of phytase converted approximately one-third of the unavailable P to an available form The results indicate that the phytase was efficacious in improving the bioavailability of phytate P for pigs

Gary L. Cromwell

Papers

Why and how antibiotics are used in swine production

Physical, chemical, and nutritional characteristics of distillers dried grains with solubles for chicks and pigs.

Brewers dried yeast as a source of mannan oligosaccharides for weanling pigs.

Growth promotion effects and plasma changes from feeding high dietary concentrations of zinc and copper to weanling pigs (regional study).

Efficacy of phytase in improving the bioavailability of phosphorus in soybean meal and corn-soybean meal diets for pigs.