Research Digest: March 2008
Additional research from the March 2008 issue of WATT PoultryUSA
Use of prebiotic compounds studied
Use of growth-promoting antibiotics in animal agriculture has caused concerns worldwide due to worry about development of antibiotic-resistant bacteria. This has prompted researchers to investigate various methods of maintaining and improving the performance of poultry in the absence of antibiotic growth promoters. Compounds that may have prebiotic effects are one possible way of improving intestinal health and performance in the absence of antibiotic growth promoters.
A prebiotic compound has been defined as a non-digestible feed ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon and thus improves gut health. Certain oligosaccharides (medium chain carbohydrates) are considered to be prebiotic compounds because they are not hydrolyzed in the upper gastrointestinal tract and are able to favorably alter the colonic microflora.
The authors conducted two experiments with chicks fed a corn-soybean meal diet, and one experiment was conducted with chicks fed a dextrose-isolated soy protein diet to examine the effects of inulin, oligofructose, mannanoligosaccharide (MOS), short-chain fructooligosaccharide (SCFOS), and transgalactooligosaccharide on growth performance, metabolizable energy (MEn), digestibility of amino acids (AA), and cecal microbial populations. Neither 4 nor 8 g of oligosaccharides/kg had a significant effect on growth performance. The MEn and AA digestibility values increased with increasing age. Feeding 8 g/kg of inulin and SCFOS had a negative effect (P < 0.05) on MEn at most ages, and 8 g/kg of most of the oligosaccharides reduced (P < 0.05) digestibility of AA at various ages.
In experiment 2, 4 g/kg of SCFOS, MOS, and transgalactooligosaccharide significantly reduced MEn at 3 to 4 days, but most oligosaccharides increased (P < 0.05) MEn values at 7, 14 and 21 days. The effects of oligosaccharides (4 g/kg) on AA digestibility were generally small and inconsistent. Feeding corn-soybean meal diets containing 4 g/kg of oligosaccharides had no significant effect on cecal Bifidobacterium, Lactobacillius, Clostridium perfringens or Escherichia coli populations in 21-day-old chicks.
In a third experiment, cecal populations of C. perfringens were reduced when SCFOS and MOS were supplemented at 4 g/kg into a dextrose-isolated soy protein diet.
The authors concluded that these results indicate that a low concentration (4 g/kg) of an indigestible, prebiotic oligosaccharide can be fed with no deleterious effects on MEn and AA digestibility. Feeding a higher level of an oligosaccharide (8 g/kg), however, may depress MEn and AA digestibility.
P. Biggs, C.M. Parsons and G.C. Fahey; 2007. The Effects of Several Oligosaccharides on Growth Performance, Nutrient Digestibilities, and Cecal Microbial Populations in Young Chicks. Poultry Science, 86: 2327-2336.
Oxihumate for aflatoxin-contaminated feedstuffs?
Aspergillus molds may infect economically important crops and forages in the field and during storage, transportation and processing. These fungi produce the highly carcinogenic aflatoxin, which contaminate food and animal feeds worldwide, causing serious health problems and livestock production losses. Unfortunately, discontinuing the feeding of aflatoxin-contaminated grain is not always practical, especially when alternate feedstuffs are not readily available or affordable.
Numerous physical, chemical and biological techniques for mycotoxin decontamination of agricultural commodities have been used; however, they have had limited success. One of the most practical approaches is the use of nonnutritive adsorbents in the feed of broilers, which bind the mycotoxins and inhibit their absorption from the gastrointestinal tract, thus minimizing the toxic effects and the carryover of these fungal metabolites into animal products. Aluminosilicates, activated charcoal, polymers, such as cholestyramine and polyvinylpyrrolidones, and yeast and yeast products have been extensively studied with promising, but varying, results.
The authors conducted a study to determine the adsorption capacity of a humic acid, oxihumate, for binding aflatoxin B1 (AFB1). Oxihumate showed a high affinity for AFB1. The efficacy of oxihumate as an aflatoxin binder in male broiler chickens, exposed to aflatoxin-contaminated feed from seven to 42 days of age was also assessed. The efficacy of oxihumate was compared with a commercially available product containing brewer’s dried yeast (BDY) and brewer’s fermentation solubles as main active ingredients.
Oxihumate was effective in diminishing the adverse effects caused by aflatoxin on the body weight of broilers (P < 0.05). Oxihumate also showed protective effects against liver damage, stomach and heart enlargement, as well as some of the hematological and serum biochemical changes associated with aflatoxin toxicity (P < 0.05). Results indicated that oxihumate, but not BDY, could alleviate some of the toxic effects of aflatoxin in growing broilers. The authors concluded that oxihumate might, therefore, prove to be beneficial in the management of aflatoxin-contaminated feedstuffs for poultry when used in combination with other mycotoxin management practices.
C. Jansen van Rensburg, J.B.J. Van Ryssen, N.H. Casey and G.E. Rottinghaus; 2006. In Vitro and In Vivo Assessment of Humic Acid as an Aflatoxin Binder in Broiler Chickens. Poultry Science, 85: 1576-1583.
Water usage survey: Turkey processing
Water has become an important natural resource because of limited availability, variable quality, increasing water and sewer costs, strict discharge requirements, and growing demands to divert supplies to residential areas that are, in many cases, growing continuously. Water is used at nearly every stage of processing, and rationing of water in drought-stricken areas can have a dramatic negative impact on poultry processors. Northcutt stated that in 2002 there were several reports from poultry processing facilities where production capacity was limited because water was scarce and supplies were highly variable.
The author conducted a survey of turkey processing facilities to determine the average volume of water used per bird during processing, the average amount of recycled processing water, and the types of poultry processing antimicrobial treatments. Ninety-three surveys were sent out to turkey processing facilities in the USA. Twenty-six surveys were completed and returned (28 percent). The combined processing capacity of the 26 facilities that responded to the survey was approximately 1.03 million birds per day or 71 percent of the total U.S. turkey production (252 million annually).
Most of the facilities that responded to the survey reported operating five days each week, using city water (85 percent) and discharging wastewater through the city sewer system (77 percent). The average amount of water used during processing was reported to be approximately 30 gallons per turkey, which is an increase of 23 percent due to the implementation of the Hazard Analysis and Critical Control Point program. Approximately 92 percent of the respondents reported using a cage- or truck-washing station. Thirty-one percent of the facilities reported that they recycle processing water.
The author concluded that data from the present survey might be of interest to turkey processing facilities that want to establish a water conservation program. One additional point is that water conservation is often in direct conflict with microbial reduction programs. Thus, water conservation efforts should always be balanced with maintaining the microbiological quality of turkeys.
J.K. Northcutt, 2007. Water Use and Reuse in Commercial Turkey Processing Facilities. Journal of Applied Poultry Research, 16(4): 652-655.
Chopped paper for turkey litter
Most commercial turkeys in the USA are grown on dirt or clay floors overlaid with some type of bedding material. Many types of bedding materials have been used to rear poultry, including straw, corncobs, cornstalks, sugarcane stalks, peat moss, peanut hulls, wood shavings and oat hulls. However, in the southeastern USA, shavings from pine or other soft wood have historically been the bedding of choice for poultry production. For turkey production, a product that more closely resembles sawdust is used.
As pine shavings have become less available, using alternative bedding materials, extending the life of currently used litter, or both continue to be explored in the turkey industry. Cotton waste, old newsprint and gypsum are all waste products that are readily available in the southeastern USA. Studies about 20 years ago with newsprint alone proved to be unsuccessful because the newsprint becomes clumped and no longer absorbs moisture.
The authors conducted two experiments and three field trials using a novel experimental litter material for growing Large White commercial turkeys. The control bedding was pine shavings (PS) in both experiments and all trials. The novel bedding, aGroChips (AC), is a chopped paper product made from cotton lint waste, gypsum and old newsprint following a proprietary paper manufacturing process.
In both experiments, hens and toms were reared according to typical industry techniques. In the first experiment, use of AC resulted in significantly (P < 0.05) heavier toms and hens. In the second, the toms brooded and reared on AC were significantly (P < 0.05) heavier than those brooded and reared on PS, whereas toms brooded on one bedding and then reared on the other were intermediate in weight. There were no differences in final cumulative FCR or carcass yield in either experiment.
Three field trials were conducted with Large White commercial turkey hens in which the hens were brooded either on PS or AC, with both groups reared on PS. There was a mean increase of 0.2 kg in BW, a decrease (improvement) of 0.03 in FCR, and an increase of 3,200 kg per trial for AC-brooded birds (based on 16,000 hens placed per brooder house). A hard, dry litter crust was observed in the AC houses. The price of this type of litter material is significantly higher than traditional materials. In areas of the country where litter materials are difficult to obtain, this option may be an acceptable one.
J.L. Grimes, T.A. Carter, A.E. Gernat and J.L. Godwin; 2007. A Novel Bedding Material Made from Cotton Waste, Gypsum, and Old Newsprint for Rearing Turkeys. Journal of Applied Poultry Research, 16(4): 598-604.