| dc.description | Poverty alleviation is one of the most important challenges of the twenty first century in
Bangladesh. Agricultural development is the main key to alleviate poverty from the
country. Livestock is the most important agricultural component which alone contributes
about 17.3% GDP to agriculture (DLS, 2014). Livestock population in Bangladesh is
currently estimated about 25.7 million cattle, 0.83 million buffaloes, 14.8 million goats,
1.9 million sheep, 118.7 million chicken and 34.1 million ducks (DLS, 2014). The
density of livestock population per acre of cultivable land is 7.37 (Banglapedia, 2012). In
spite of a high density of livestock population, the country suffers from an acute shortage
of livestock products like milk, meat and eggs. The shortage accounts for 85.9%, 88.1%
and 70.7% for milk, meat and eggs, respectively (Banglapedia, 2012).Biotechnology
plays a vital role in the poultry feed industry. Nutritionists are continually putting their
efforts into producing better and more economical feed. Good feed alone will not serve
the purpose but its better utilization is also essential. Dietary changes as well as lack of a
healthy diet can influence the balance of the microflora in the gut thus predisposing to
digestion upsets. A well-balanced ration sufficient in energy and nutrients is also of great
importance in maintaining a healthy gut. A great deal of attention has recently been
received from nutritionists and veterinary experts for proper utilization of nutrients and
the use of probiotics for growth promotion of poultry (Kabir, 2009). Probiotics are live
microbial complements that leave useful effects on the host through an improvement in
the intestine’s microbial equilibrium (Fuller, 1989). Different microbial species such as
bacteria (Bacilli, Bifidobacteria, Enterococcus, Lactobacillus, and Streptococcus), yeasts
(Saccharomyces cerevisiae), fungi (Aspergillusoryzae and Aspergillusniger) and
indefinite mixed cultures have been used as probiotics (Simon et al., 2001). Protexin®
and AM Phi-Bact are a kind of commercial bacterial probiotic that contains entrococcus
faceum and lactobacillus species respectively. For many years, antimicrobial compounds
have been used in the poultry breeding industry for improvement in health status and
performance of birds by reduction or correction of the population of the bacteria present
in the gastrointestinal (GI) tract (El-Katcha1 et al., 2012, Fairchild et al., 2001).
Microorganisms used as probiotics in animal nutrition: Probiotics are live
microorganisms that, when administered through the digestive tract, have a positive impact on the host's health. Microorganisms used in animal feed are mainly bacterial
strains belonging to different genera, e.g. Lactobacillus, Enterococcus, Pediococcus and
Bacillus. Other probiotics are microscopic fungi, including Saccharomyces yeasts. Some
probiotic microorganisms are normal residents in the digestive tract, while others are not
(Hassanein and Soliman, 2010, Guillot, 2009). The different mechanisms of action
suggested are: (i) nutritional effect include: (1) reduction of metabolic reactions that
produces toxic substances (2) stimulation of indigenous enzymes (3) production of
vitamins or antimicrobial substances. (ii) sanitary effect include (1) increase in
colonization resistance. (2) stimulation of the immune response (Hassanein and Soliman,
2010).Some experiments have demonstrated in vitro the effects of strains of
Saccharomyces cerevisiae on the activity of anaerobic rumen microorganisms. The
addition of S. cerevisiae live cells to cultures of some cellulolytic fungal species
stimulated zoospores germination and cellulose degradation. The addition of yeasts
stimulates also the growth of some anaerobic bacteria, including the cellulolytic and the
lactic acid utilising bacteria (Hassanein and Soliman, 2010, Chaucheyras et al., 1995;
Yoon and Stern, 1996). Kizerwtter and Binek, (2009) reported that probiotics have
reduced the incidence and duration of diseases. Probiotic strains have been shown to
inhibit pathogenic bacteria both in vitro and in vivo through several different
mechanisms. The mode of action of probiotics in poultry includes: (i) maintaining
normal intestinal microflora by competitive exclusion and antagonism (ii) altering
metabolism by increasing digestive enzyme activity and decreasing bacterial enzyme
activity and ammonia production (iii) improving feed intake and digestion iv) stimulating
the immune system (Apata, 2008; Kabir, 2009). The addition of probiotics to diets
benefit the host animal by stimulating appetite (Nahashon et al., 1992), improve
intestinal microbial balance (Fuller, 1989), stimulate the immune system (Toms and
Powrie, 2001), decrease pH and release bacteriocins (Rolfe, 2000) that compete with
other microbes for adhesive site, improve egg mass, egg weight, egg size in layers
(Mohiti et al., 2007; Nahashon et al., 1992; Jin et al., 1997) and feed consumption in
layers and also depress serum and egg yolk cholesterol concentrations in hens (Mohiti et
al., 2007; Mohan et al., 1995; Kurtoglu et al., 2004) | en_US |
| dc.description.abstract | The study was carried out to assess, examine and quantify the effect of Probiotics
(Protexin, Exolution) and Antibiotic (Renamycin) supplementation on egg production
performance and microbial load of laying hens at the latter stage (56-63weeks) of
production. The study was conducted at the poultry farm and Microbiology laboratory,
Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur. Total
48 Hisex Brown hens of 56 weeks old were allocated to 4 treatments with 3replications,
each containing 12 hens. The hens in individual cages were supplied feed 120 g/b/day
(not fixed) containing 18.21% CP and 2762.21 ME KCal/kg diet. Laying hens were
randomly allotted to 4 dietary treatments T0 (control), T1 (Protexin-30gm/100kg of feed),
T2 (Exolution--60gm/100kg of feed), T3 (Renamycin -100gm/100kg of feed).There were
no significant effect on body weight shown after the experiment. Egg production was
more or less similar at first few weeks, but at later stage results showed increased
production in T1 and T2 Treatment than the control T0. The egg weight was gradually
increased in T2 (67.84g in 8th week) treatment group. The highest egg weight was found
in T2 (67.84 gm). The feed intake of laying hens in different dietary treatments during
experimental period was almost similar .The feed efficiency(FE) in different dietary
treatments were statistically significant and the best FE was found in T2 (1.75 in 5th
week) treatment group .Other treatment group like T1, T3 have also better FE than that of
control group. Supplementation of Protexin, Exolution and Renamycin in the diets
significantly decreased the population of harmful bacterium, Escherichia coli, and total
culturable bacteria than those of control. | en_US |
