ABSTRACT
A sixty three (63) day experiment was carried out to bio-appraise different non-antibiotic growth enhancers using one hundred and twenty day-old broiler chicks (DOC). The DOC were randomly assigned to four treatments of 30 birds per group, each with three replications (10 birds per replicate), in a completely randomized design (CRD). T1 served as the control (CT), whereas T2, T3 and T4 had commercially procured ElRox (EX), PolaMix (PX) and MaxiGrowth (MX) growth promoters incorporated at 400g/100kg, 500g/100kg and 600g/100kg respectively. Data were collected weekly on body weight, body weight gain, daily feed intake, feed conversion ratio, protein efficiency ratio and feed cost per Kg gain. Carcass yields of the experimental groups were also evaluated at the end of the experiment. Biochemical parameters of the bird were also determined at the end of the experiment. These were protein profile, liver enzymes, bilirubin, lipid profile and serum arsenics. Results of this study showed that the non-antibiotic growth enhancers used in the study had a significant (P<0.05) effect on the performance characteristics of the experimental birds. The birds that received ElRox (T2) had better results in the overall performance indices of the experimental animals, including feed cost/Kg gain. Birds on the ElRox in-feed diet had significantly (P<0.05) the best edible meat parts. However, there was no significant (P>0.05) difference in the liver enzymes and bilirubin levels. Effect of treatments on the serum arsenic levels was significant (P<0.05). It was higher in the birds that consumed in-feed MaxiGrowth. Treatments effects on the protein profile of the birds were significant (P<0.05). Birds on control diet had the highest protein level while those on the PolaMix had the least. The urea and creatinine levels were not significantly (P>0.05) affected by treatments. In the same vein, lipid profile (CHOL, HDL, VLDL, and TRIG) were also not significantly (P>0.05) affected except LDL. The highest level of LDL was recorded in birds on the control diet, with PolaMix as the least. The results of the overall experiment indicated that, of all the non-antibiotic growth enhancers examined, only ElRox promoted a significant weight increase with better cost benefit return. It is concluded that feeding ElRox (400g/100kg) to broilers resulted in better performance of the birds.
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background Information.
The importance of meat in the diet of man cannot be overemphasized. Apart from other dietary roles meat plays, they remain one of the sources of most essential amino-acids for normal growth. Livestock farmers in an attempt to improve the growth of their animals have used substances that can enhance growth and sustain their animals on a healthy status. One of such substances that has been widely used is antibiotics.
Antibiotics are used at low doses in animal feeds, and are considered to improve the quality of the product with a lower percentage of fat and higher protein content in the meat (Brussels, 2005; Hughes and Heritage, 2003). Antibiotics have been used to prevent and control bacterial infections as well as growth promoters. Prevention and control of bacterial infections have been achieved by a therapeutic, metaphylactic or prophylactic application of antibiotics. Other benefits of the use of antibiotic growth promoters include control of zoonotic pathogens such as campylobacter, E. coli, and enterococei (Brussels, 2005).
According to the National Office of Animal Health (NOAH, 2001), antibiotic growth promoters are used to “help growing animals digest their food more efficiently, get maximum benefit from it and allow them to develop into strong and healthy individuals”. More clearly the term “antibiotic growth promoters” describes any medicine that destroys or inhibits bacteria, and is administered at a low, sub-therapeutic dose (Casewell et al., 2003). The use of anti-biotic growth Promoters in the European Union was approved by the Council Directive of 23 November 1970 concerning feed additives (FDA, 2013).
However, there has been controversy surrounding the use of antibiotics as growth promoters in animal nutrition (Hughes and Heritage, 2003). It has caused a number of negative changes. It influenced, among others, development of drug resistance in bacteria. Livestock are a major reservoir of bacteria resistant to antibiotics. These pathogens contained in animal meat entered human body and quickly spread in human society.
The European Union banned on the application of antibiotic growth promoters in feeds for animals bred for consumption in 2006. The ban was introduced at the same time in all countries of the Union. Since that time, antibiotics have been allowed to be used as drugs only in medicinal animal feeds or in prophylactic additives. The Regulation EC No 1831/2003 of the European Parliament and Council dated 22 August 2003, on the additives used in animal nutrition, includes, among others, probiotics as feed additives alternative to antibiotic growth promoters (Casewell et al., 2003).
Alternatives to antibiotics therefore are probiotics, phytogenics, organic acids growth enhancers etc. Lilly and Stillwell (1965) described probiotics as microorganisms stimulating the growth of other microorganisms. The term was used by Parker (1974) for organisms and substances that contribute to balancing the intestinal micro flora of the host. Many bio-active ingredients according to Wang et al. (1998) and Wenk (2000) which include alkaloids, bitter flavonoids, glycosides, mucilage, saponins and tanins are new generation growth promoters. As herbs and plant extracts, they act on the appetite and intestinal micro flora, stimulate the pancreatic secretions to increase endogenous activity and immune system.
Prebiotics on the other hand are non-digestible food components/ingredients which have positive effect on host in their selective growth and/or activation of certain number of bacterial strains present in intestines (Gibson and Roberfroid, 1995).
Synbiotics on its part is a relatively recent term among additive used in poultry nutrition. They are combination of probiotics and prebiotic as well as other promoting substances which together exhibit joint effect in regard to health of digestive tract, digestibility and performance of broilers (Fuller, 1989). Investigation showed that combinations used in synbiotic are often more efficient in relation to individual additives (Li et al., 2008).
Acidifiers have been used in poultry nutrition especially the organic acids. The organic acids reduce the pH value of food and in this way act as conserving agents and prevent micro biological/ microbial contamination of food, and this effect is exhibited also in digestive tract of poultry (Eidelsburger and Kirchgessner, 1994; Freitag et al., 1995).
More commonly found in the Nigerian markets are some of the widely used non-antibiotics growth enhancers. Some of these non-antibiotic growth enhancers contain active ingredients some of which have been banned, while others have innate growth promoters like enzymes. For instance ElRox contains Roxarsone as an active ingredient.
However, the American Feed Industry, now Food and Drug Agency (FDA) have legally withdrawn the production and marketing of three drugs used in Poultry and Pig feeds as opposed to Nigerian Market situations. These drugs are: Roxarsone, Carbarsone and Arsanilic acid. This regulation took effect after FDA studied 100 broiler birds and detected inorganic arsenics which are known carcinogens at higher levels in the liver of chicken treated with Roxarsone than in the untreated ones; ensuring that Pfizer Company stops the production and marketing of Roxarsone and its products (FDA, 2013). However, there still exist different brands of purported non- antibiotic growth enhancers in the Nigeria market. Farmers are lured to use these promoters because of the manufacturers’ claim that they enhance growth.
The label of ELROX as found in Nigeria markets indicates a contra-indication leading to weak leg condition in growing bird in excessive use; each gram containing 5mg of Roxarsone. The inclusion rate being 100g per bag of poultry feed (25kg), it has advisory indications of being fed to the animals from day- old for best results, improve pigmentation in animal, enhances optimum digestion and absorption of nutrients, eliminates undesirable bacteria, enhances the synergetic function of antibiotics and coccidiostats and help reach marketable weight sooner thereby reducing overall cost of feeding. MaxiGrowth, another compared commercially available growth enhancer indicates vitamin complexes, micro-elements, macro-elements and amino-acids for improved feed utilization and acclaimed maximum weight gain. Its application rate corresponds to 150g per 25kg. Polamix is acclaimed to be a growth booster, immune booster, encourages weight gain, mops up toxin, and encourages vibrancy, comb increase, and luxuriant/streamed lined feathers. Its application rate corresponds to 125g per 25kg.
There appears to be no literature evidence on the mode of operation of these non-antibiotic growth enhancers. Do these non-antibiotic growth enhancers really improve performance? If they do, what effect do they have on the biochemical and carcass characteristics of the birds? These and other questions form the research thrust of the present study
1.2 Statement of Problem.
There has been an inflow of various non-antibiotic growth promoters in Nigeria. The farmers who patronize these promoters do so on the firm believe that performance of their birds will be enhanced. The mechanism by which these growth promoters function is not clearly defined. There exist no on-farm or on-station trials to validate the claims of manufacturers of these products. Some of them have potential active ingredients already banned by International Regulatory Agencies. It is important therefore to carry out feeding trials and validate the claims about these products to inform farmers that may wish to use them.
1.3 Objectives of the Study
This study is aimed at appraising the use and acceptability of non-antibiotic growth enhancers found in the market as alternatives to antibiotic growth promoter in broiler feeds.
The specific objectives of the study were to:
I. Determine the performance broiler birds given different non-antibiotic growth promoters.
II. Determine the effect of dietary inclusion of different non-antibiotics growth enhancers on biochemical parameters of broiler birds.
III. Determine the carcass yield of broiler birds fed different non-antibiotic growth enhancers.
IV. Determine the reduction potential of muscular cholesterol values by the non-antibiotic growth potentials.
V. Determine the cost implication of including different non-antibiotic growth enhancers in the diet of broiler birds.
1.4. Justification of the Study
Users of various non-antibiotic growth enhancers have long been in doubt of performance status of these promoters comparatively. Fears also assail the minds as to the toxic free nature of the arsenic based products since their ban by the European Union.The research on the bio-evaluation of different non-antibiotic growth enhancers would yield a result that will be beneficial to all farmers and users of the bio-evaluated growth enhancers. Since the extent of growth promoting effect of some of the commercially procured growth promoters has not been comparatively ascertained as well as the bio-toxicity of the acidic based products, farmers and all consumers of broilers fed these non-antibiotic growth enhancers will therefore be aware of the status.
This material content is developed to serve as a GUIDE for students to conduct academic research
BIOAPPRAISAL OF DIFFERENT NON-ANTIBIOTIC GROWTH ENHANCERS USING BROILERS
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