ABSTRACT
A preliminary study was carried out to determine
the prevalence of Aflatoxin B1 (AfB1) contamination and common moulds growing
in some selected poultry feed ingredients in Zaria town, Nigeria. Twenty-five
(25) samples of five different feed ingredients, which included Maize (MZ),
soybean cake (SBC), groundnut cake (GNC), brewers dried grain (BDG) and maize
offal (M/O) were collected. Samples were collected in March from four
commercial feed mills and the open market. The common moulds isolated from the
samples were Mucor spp., Aspergillus s
pp., Fusarium spp., Penicillum spp.,
Curvularia spp. and Rhizopus spp.
Aflatoxin B1 contaminationshowed
that maize and soya bean cake were less than the 20 parts per billion (ppb)
permissible limits for AfB1 in poultry feed ingredients, while BDG, M/O and GNC
were 40, 60 and 80 % respectively above 20 ppb permissible limits. Three
feeding trials were conducted using broiler chickens. The first experiment was
conducted to evaluate the effect of four levels of Mycofix® in diets of broiler chickens,
experiment two evaluated the response of broiler chickens fed diets containing
four levels of
Biotronic ® SE and experiment three evaluated the response of broiler chickens fed
diets containing single and combined levels of Mycofix® and Biotronic ® SE. In experiment one; 330 day
old Ross broiler chicks were used for the feeding trial. The chicks were
allotted in a completely randomized design (CRD) to five dietary treatments
replicated thrice with 22 chicks per replicate. Treatment one was the control
diet without Mycofix®, while treatments 2, 3, 4 and 5 had Mycofix® included at the rate of 100,
200, 300 and 400 g / 100kg diet respectively. In experiments two and three, a
total of 396 day old Ross chicks each were used. In experiment 2, Treatment one
was the positive control diet without Biotronic® SE and Oxytetracycline,
treatments, 2, 3, 4, 5 had Biotronic® SE at the rate of 200, 300, 400, 500g Biotronic® SE / 100kg diet and Tretment 6
(negative control) had 100g Oxytetracycline/100kg feed. Experiment 3, Treatment
one was the postive control diet without Mycofix®, Biotronic® SE and Oxytetracycline,
treatments 2, 3, 4, 5 had 400g Mycofix®, 500g Biotronic® SE, 200gMycofix® + 250 Biotronic® SE, 400g Mycofix®+ 400g Biotronic® SE and treatment 6 (negative control) 100g Oxyteracycline/ 100kg of
feed respectively. The diets were formulated to meet standard requirements for
starter and finisher broiler chickens. Feed and water were given to the birds ad libitum for the experimentl periods.
Data collected included the average of body weight gain, feed intake, feed conversion ratio, carcass percentage, nutrient digestibility; others were
haematological, biochemical indices, kidney function test, microbial analysis
of digesta, drug residue in meat samples and villi morphometerics. Data
collected were subjected to Analysis of Variance (ANOVA) using General Linear
Model procedure of SAS and significant differences among treatment means were
compared using Dunnette test of significance. Experiment One, starter phase
showed that dietary treatments had significant effect (P
- 0.05) on final weight gain, feed
conversion ratio, feed cost and feed cost per kilogram gain. Birds fed
400g/100kg diet Mycofix® had the best final body weight gain at both starter (839.67g) and
finisher phases (2350.34g) respectively. The feed conversion ratio at the
starter phase was significantly (P<0.05) lower in the experimental
treatments and at the finisher phase, 400g Mycofix® treatment had a significantly
(P<0.05) lower feed conversion ratio. There were no significant differences
(P<0.05) across treatments for cut parts and organ weights of carcass.
Haematological and biochemical indices were not significantly affected by
dietary treatments as parameters were within the normal reference range for
broiler chickens. Nutrient digestibility was significantly improved at 400g
inclusion. Experiment Two,
xvii
starter phase results showed
similar (P>0.05) weight gain in birds on 500g Biotronic® SE and100g Oxytetracycline. The
birds fed 500g Biotronic® SE had the best feed conversion ratio (1.7) and feed cost per kilogram
gain (₦151.42) values. The finisher phase result showed no significant
(P>0.05) differences in weight gain among Treatments 3, 4, 5 and 6. Birds on
400g Biotronic® SE had a lower (P > 0.05) FCR and feed cost per kilogram gain.The
dressing percentage for the carcass was best in 500g Biotronic® SE and Oxytetracycline
treatments. Prime cuts: breast, drumstick and wings were better in birds on
400g Biotronic® SE. Haematological parameters were not affected by dietary treatments.
The values of alkaline phosphatase (ALP) were significantly (P>0.05) higher
in the experimental treatments, alanine amino transferase (ALT) values was
significantly (P>0.05) higher in the antibiotic treatment while aspartate
aminotransferase (AST) values was significantly (P > 0.05) higher in birds
on 400g Biotronic® SE and Oxytetracycline group. The crude protein values (86.54, 89.31
and 94.50 %) for nutrient digestibility was significantly (P<0.05) higher in
200, 300 and 400g Biotronic® SE groups respectively. The crude fibre (76.43 %) and ether extract
(89.82 %) values were significantly (P<0.05) lower across treatments. The
levels of Biotronic® SE was more effective in increasing aerobic plate count and coliform
counts in both ileum and ceacum of broiler chicks. Birds fed the control diet
showed no drug detected, while birds fed 200, 300, 400 and 500g Biotronic® SE were low and Oxytetracycline
treatment showed high concentration of drug. In experiment three, results of
the starter phase showed no significant (P>0.05) differences in most of the
parameters measured across treatments. Birds on Oxytetracycline treatment had a
significantly (P <0.05) higher feed intake (1920.44g) from the rest
treatment groups and control. At the finisher phase, birds on 100g
Oxytetracycline had a significantly (P
- 0.05) higher weight gain, average daily weight gain and feed conversion ratio and least feed cost /kilogram gain Carcass result showed better breast weight for birds fed diets with Oxytetracycline and better drum stick for birds fed diets with 400g Biotronic® SE. No significant (P>0.05) differences for organ weights across treatments. No significant (P>0.05) differences were recorded across treatments for haematological profile, liver and Kidney function tests. Nutrient digestibility for birds fed 400g Biotronic® SE was better (P<0.05) in its percentage composition for dry matter, crude protein, crude fibre and ash content across treatments but similar to control. Results of villi morphometrics of sections of the jejunum showed that birds fed 400g® Mycofix and 400g Biotronic® SE had a significantly (P<0.05) higher villi crypt across treatment groups and control. Villi roundness for birds on control diet was significantly (P<0.05) higher other rest treatment groups. The study concludes the growth of fungi spp. in feed ingredients samples and presence of AfB1. The findings of the feeding trials concludes that the use of Mycofix® a toxin binder, improved performance significantly at both starter and finisher phases at the rate of 4kg/tone which was above the recommended level of 2-3kg /tone. The use of Biotronic® SE as a gut acidifier gave a better result for all the growth performance parameters above the control; at 500g/100kg for starter phase and 400g/kg at finisher phase. It had a positive effect on maintenance of normal microbial activity of ileum and ceacum and no residues in meat samples. The combined and single use of Mycofix® and Biotronic® SE did not significantly improve growth of broiler chickens, but performed comparable to the antibiotic treatment in all the parameters measured. The combinations had no adverse effect on measured performance parameters, haematological parameters, liver and kidney function tests and improved villi crypt an evidence of a positive synergy in their combination. It is recommended that Mycofix® can be singly used at 400g/100kg and 500g/100kg feed of Biotronic ® SE as a means of alleviating the incidences of mycotoxins in feed and improving gut health.The combined inclusion recommended is at 200g Mycofix® and 200g Biotronic ® SE/100kg feed.
CHAPTER
ONE
1.0
INTRODUCTION
Feed represents the greatest single expenditure associated with poultry production. Nutritional research in poultry has therefore centered on issues related to identifying barriers to effective digestion, utilization of nutrients, and on approaches for improving feed utilization (Ravindran, 2010). The quality of feed ingredients is very important as this will determine the quality of the feed and the end-products.Hence a more precise evaluation of the quality of dietary raw materials is needed (Kersten et al., 2005). Feed materials may be contaminated at any time during growing, harvesting, processing, storage and distribution of the feed. Feeds may contain diverse microflora that are acquired from multiple environmental sources, including dust, soil, water, and insects (Maciorowski et al., 2006).
Mycotoxins are a historical problem in poultry, first recognised in the 1960s as the cause of ‘turkey X disease’ in England which resulted in the death of 100,000 turkey poults and many ducks, chickens and pheasants (Siska, 2013). Mycotoxins are toxins formed during fungi growth, myco means mould and toxin represents poison (Annongu, 2012). Mycotoxins are highly toxic secondary metabolic products of mould on almost all agricultural commodities worldwide. They occur under natural conditions in feed. Several studies proved that economic losses occur at all levels of food and production, including crop and animal production, processing and distribution (Robens and Cardwell, 2003; Wu, 2007; Bryden, 2012). According to the Food and Agriculture Organization (FAO), 25% of the world‟s crop harvests are contaminated with mycotoxins (FAO, 2012). There are currently more than 400 mycotoxins known. There are six major classes of mycotoxins that frequently occur namely, aflatoxins, trichothecenes, fumonisins, zearalenone, ochratoxin and ergot alkaloids (CAST 2003). They are formed by different kinds of fungi and each fungi species can produce more
than one type of mycotoxin.
Surveys of mycotoxin levels in poultry feeds often reveal the presence of a
number of different toxins; most samples in a recent survey contained at least
10 contaminants. Contamination of feeds with mycotoxins is a worldwide problem,
in poultry particularly those produced by the genera, Fusarium, Aspergillus and Penicillium (Siska, 2013).
Mycotoxin binders or adsorbents are substances that
bind to mycotoxins and prevent them from being absorbed through the gut and
into the blood circulation (Jacela et
al., 2010). The addition of mycotoxin binders to poultry diets has been considered
the most promising dietary approach to reduce the effects of mycotoxins
(Galvano et al., 2001). The theory is
that the binder decontaminates mycotoxins in the feed by binding them strongly
enough to prevent toxic interactions when the animal consumes the feed and to
prevent mycotoxin absorption across the digestive tract.
Nutritional researchers have therefore implored the
use of toxin binders as an approach to salvaging feed contamination with
mycotoxins and protecting animals from disease problems and losses in
performance. Another approach by researchers is the use of dietary
supplementation with acidifiers, which are organic acids used to reduce
bacterial growth. It helps to reduce colonization of pathogens on the
intestinal wall, thus preventing damage to the epithelial cells. Acidifiers
enhance increase in body weight and feed conversion ratio in broiler chicken
(Skinner et al., 1991).
The Mycofix® product line from BIOMIN is a range of specially developed feed additives that protect animal health by deactivating mycotoxins found in contaminated feed. Its modular system consists of three strategies: Adsorption – Elimination of toxins, Biotransformation – Elimination of toxicity and Bioprotection – Elimination of toxic effects. Mycofix is one of the new promising mycotoxins
adsorbent that was successfully used to alleviate the negative effects of T-2
toxins in broilers (Aziz, 2005; Omar, 2010).
Biotronic® SE is a powerful combination of synergistically acting organic acid and
their salts combined on a Sequential Release Medium (SRM). Besides decreasing
pH, the selected acids penetrate the cell wall of gram – negative bacteria. The
use of Biotronic® SE is indicated for the control of gram – negative bacteria including E. coli and Salmonella in other to promote animal growth in pig and poultry.
This highly effective synergism ensures its full economic benefit (Poultry
Site, 2014).
1.1 Justification for the Study
One subject receiving much attention from researchers at present is that of mycotoxicity. It is an issue which has important implications for the global feed industry, bird performance and potential with negative consequences for the food chain (Stephen, 2008). Nigeria does not have standard regulationsand control on mycotoxins in poultry feed, consequently the risk of mycotoxins exists in the Nigerian poultry sector since the common feed ingredients, such as maize and groundnut cake, are known to contain high levels of mycotoxins (Kpodo and Bankole, 2008). Fungi are major spoilage agents of foods and feedstuffs. The proliferation of various fungi species in agricultural products leads to reduction in yield and quality with significant economic losses (Adejumo and Adejoro, 2014).
The poultry industry witnessed a tremendous growth with the best application of nutritional technologies. Today, animal feed production has been paid attention; however, feed safety is a concern for achieving productivity. Mycotoxin contamination of feed is a recurring problem, however the effective control is a challenge because the mycotoxins contamination occurs through various feed raw materials, which are used in poultry feed. Nevertheless the contamination of mycotoxins can
come from the dust and leftover feed in the feeding channel; hence a rational
approach has to be adopted for effective control of feed mycotoxins (Bhat,
2011).
On the other hand, gut health is currently gaining much more attention in literature especially in poultry and has been applied to coordinate the working efficiency of the gut (Laudadio et al., 2012). The gut is the most extensive exposed surface and is constantly exposed to a widevariety of potentially beneficial, non-infectious as well as harmful infectious pathogens (Lievin-Le Moal and Servin, 2006). This has necessitated the need to tackle the microbial population in the gut of the chicks as early as they are hatched in favour of the beneficial microorganism in the host. This is achievable by the use of acidifiers which plays the role of lowering the pH of the gut, thereby inhibiting the proliferation of pathogenic micro-organisms hence, reducing their adverse effect on the host animal.
The use of a toxin binder to mitigate the effect of
mycotoxins present in feed and an acidifier to improve the gut health as a way
of improving performance was considered in the study
EVALUATION OF THE OPTIMUM INCLUSION LEVELS OF MYCOFIX AND BIOTRONIC SEAS FEED ADDITIVES ON THE PERFORMANCE OF BROILER CHICKENS
