Feed utilization

Seefeld, M.D. and R.E. Peterson. 1984. Digestible energy and efficiency of feed utilization in rats treated with 2,3,7,8-tetrachIorodibenzo-p-dioxin. Toxicol. Appl. Pharmacol. 74 214-222. 

The advisability of using certain antibiotics, particularly penicillin and tetracycline, in animal feeds has been questioned because of their use in human medicine. Any use of an antibiotic that is prescribed for humans presents some risks to human health, whether the use is for humans, animals or for other purposes but. the uses also have benefits. Otherwise, they would not persist. Antibiotics are used in animal feeds to increase animal weight, increase efficiency of feed utilization, increase reproductive efficiency and decrease morbidity and mortality. These benefits to animals and animal producers are reflected in decreases in food costs to humans. There are also benefits to human health from use of antibiotics in food animals. By reducing the incidence of animal health problems, use of antibiotics in food animals reduce the transference of animal infections to humans. The contention that the effectiveness of penicillin and tetracycline for use in human medicine is rapidly diminishing as a result of the proliferation of resistant bacteria caused by subtherapeutic use of antibiotics in animal production is not supported by experimental data. Rather, the evidence suggests that a fairly stable level of resistance of the intestinal bacteria in humans has long since been established to penicillin and tetracycline as it has been in animals. 

The exact mechanisms of how pharmaceuticals, especially antibiotics, exert growth promotion attributes in fivestock are not clearly known, but it is suspected that the antibiotics ease minor infections that do not make the animals sick, ultimately increasing feed utilization (Ferber, 2003). In practice, most of the antibiotics are used for both purposes. In the European Union, the nontherapeutic use of most antibiotics for agriculture has been banned, leaving only four compounds, that is, avilamycin, monesin, flavophsophofipol, and salinomycin, in use for nontherapeutic... 

Tannin protein binding has long been known to have an economic impact on feed utilization by domestic animals, but adverse effects in humans have only rarely been demon-strated, although they may have been overlooked during famines. These interactions in the gastrointestinal tract were once thought to be comparatively nonspecific but evidence is accumulating that there may also be more specific interactions." ... 

Glucanase -Glucans of barley oats Reductions of sticky droppings Improved feed utilization... 

Fig. 6.4). The avilamycin complex is produced by Streptomyces viridochromo-genes and is composed of factor A as the major component with several other minor components (20). It is used as a feed additive for swine at a level of 20-40 ppm for animals up to 4 months of age and at 10-20 ppm for animals of 4-6 months of age (21, 22). When fed to swine, avilamycin causes an increase in gain rate and efficiency of feed utilization. 

The most widely used and researched growth promotant of this type is the polyether antibiotic monensin (63). Monensin, at levels of 33 p.p.m. in feed, has been shown to increase efficiency of feed utilization in both sheep and cattle fed a variety of rations by up to 12%. Slaughter and carcass analysis data indicate that the main effect of the compound is to increase the efficiency of dietary energy retention in the carcass. Its mode of action is thought to be related to its ability to increase the molar proportion of propionate, at the expense of acetate and butyrate, produced in rumen fermentation probably by an effect on the relative microfloral populations. Theoretically this should make more energy available to the animal. 

ANTIBIOTICS ELFAMYCINS. The elfamyans are so named because they exhibit antimicrobial activity through the inhibition of protein biosynthesis via binding to the Wongation factor Tu. All of the known elfamyans are listed in Table 1. These antibiotics are distinguished by low mammalian toxicity, narrow-range antimicrobial activity, and positive effects on feed utilization and growth promotion in farm animals. Elfamyans also improve milk production in lactatmg ruminants. 

The effect of enzymes, recorded in many feed trials, includes increased final weight of the animal, better feed utilization, improved feed conversion ratio (FCR), more homogeneous production, reduced mortality, and a reduced amount of sticky droppings (in chickens) (87). 

An advantage of pelleting is that it may improve both intake and the efficiency of feed utilization, particularly with fibrous ingredients such as wheat milling by-products. A further advantage of pelleting is that it can help to reduce microbial counts in the feed. 

Seefeld MS, Peterson RE. 1984. Digestible energy and efficiency of feed utilization in rats treated with... 

The relation of body weight development food intake is an important parameter in toxicology studies. Normal feed uptake connected with lower body weight body development can indicate an effect on feed utilization (metabolic disorders e.g. caused by hyper-thyreoidism) or vica versa hypo-thyreoidism in case of normal food intake but faster body weight development. 

Sorbic acid is not only suitable for preservation of feedstuffs but also improves the feed utilization and weight gain of chickens. This has proven to be of economic value under practical conditions when sorbic acid is added to the feed at 0.02—0.04 wt % (143—145). Similar effects have been observed for the use of sorbic acid in swine feeds (146). 

There are problems associated with the use of copra cake in feed. As the amount of cake in the feed increases, its palatabihty decreases. Copra meal tends to be less digestible than fresh coconut meal. Despite a protein content of greater than 20%, the addition of methionine and lysine improves growth and feed utilization. The method of oil extraction does not appear to influence the quality of meal produced. Neither expeller-extracted nor solvent-extracted copra meal, at levels of 10-14% in poultry diets, caused any difference in egg production, mortahty, or efficiency of feed conversion (61). 

The major component of manufacturing cost is, quite obviously, raw materials. Hence, costs are quite sensitive to feed utilization and feed prices. The high selectivity of the Kellogg process is important in this respect. The eflFect of feed price on DCE cost is illustrated below, where costs for all HCl feed operation, with fresh HCl at 1.5 cents/lb. are compared on the basis of 3.0 as well as 4.0 cents/lb. ethylene ... 

Large quantities of feed are produced daily, transported, and stored, and even a minor contamination with pathogens, for example, Salmonella, has the potential to affect many herds (Sauli et al., 2005). To enhance the nutritional value of feed, large-scale producers treat their feed with organic acids or heat, or both. Dietary inclusion of organic acids has been found to positively affect the growth rate and efficiency of feed utilization (Giesting and Easter, 1991 Mroz et al., 2000), whereas heat treatment... 

Hydrotreating processes differ depending upon the feed utilized and the catalysts used. Typical catalysts for hydroproceesing were described in the preceding section. 

Even more complex is the structure of monensin, a compound which has been extensively used as an anticoccidial agent for poultry and shown to improve the efficiency of feed utilization in ruminant animals. When submitted to a culture of Sebekia bevihana, monensin was first quantitatively converted by enzymatic reduction of the 8-hydroxy-ketone (which is in equilibrium with its hemiketal tautomeric form) and was regioselectively further hydroxylated at the C-29 methyl group as well as at the nearby ethyl group substituent[94). 

Examination of the literature on the chemical modification of proteins and protein-containing products derived from soybeans reveals that the major motivation for such studies was often the development of improved products for industrial rather than food or feed utilization (21, 22, 23, 24). Such research activity was at the heart of the Chemurgic movement begun in the early thirties. Hence it becomes understandable that the patent literature dealing with the chemical modification of soy protein products is much more extensive than the periodical literature. This, together with our imperfect understanding of the basic structure of the soy proteins, explains why many of the reactions cited in this... 

Honeyeield DC and Forseth JA (1985) Effects of dietary sodium and chloride on growth, ffidency of feed utilization, plasma electrolytes and plasma basic amino adds in young pigs. J Nutr 115 1366—1371. 

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