eChapters

Introduction

The original concept of feeding bacterial direct fed microbial (DFM) to livestock was based primarily on potential post–ruminal effects, including improved establishment of beneficial gut microflora (Fuller, 1999). Calves fed Lactobacillus acidophilus have been reported to have reduced incidence of diarrhoea (Beecham et al., 1977) and reduced intestinal coli form count (Bruce et al., 1979). But now it is known that certain bacterial DFM also have beneficial effects in the rumen and one of the important groups of this type of bacteria is propionic acid producing bacteria (Elsden, 1945; Johns, 1951a; Langa, 2010). This group of bacteria includes Propionibacterium spp., Veillonella spp., Megasphaera spp., Selenomonas spp. and Succiniclasticum spp. (Table 1). Propionic acid producing bacteria (PAPB) are secondary bacteria which enhance propionate production by utilizing the end products of primary fibrolytic or starch utilizing bacteria which produce succinic acid and lactic acid (Swenson and Reece, 1996). Inoculation of in vitro fermentation with the lactate utilizing ruminal bacterium Megasphaera elsdenii prevented lactate accumulation and produced propionic acid when a highly fermentable substrate was used (Kung and Hession, 1995). Propionibacteria are also rumen active bacteria which can produce propionic acid by utilizing glucose, lactic acid and succinic acid (Elsden, 1945; Grinstead and Barefoot, 1992; Hugenholtz et al., 2002). Ghorbani et al. (2002) also reported that Propionibacteria convert lactate and glucose to acetate, propionate and CO₂. They also reduce nitrate to nitrite and reduce nitrite load by 40-60% and minimize changes in blood nitrite and met hemoglobin (Rehberger et al., 1993). Succinic acid is an important end–product, but in practice this is converted into propionic acid by other bacteria such as Selenomonas ruminantium (Swenson and Reece, 1996; McDonald et al., 2002; Langa, 2010); such interactions between microorganisms are an important feature of rumen fermentation. Veillonella gazogenes are also active in the rumen and produce propionic acid by fermenting succinic acid (Johns, 1951a). Moreover in low quality forage-based diet Fibrobacter succinogenes are predominant fibrolytic bacteria which digest fibre faster and produce sufficient amounts of succinic acid in the rumen (Cheng et al., 1984; Miron and Ben-Ghedalia., 1992) and synergistic increases in propionate production and fiber digestion was found in co-cultures of Fibrobacter succinogenes and Selenomonas ruminantium (Sawanon et al,2003), and of Ruminococcus flavefaciens and Selenomonas ruminantium (Sawanon et al., 2006). These findings suggest that positive interactions occur between bacteria, mostly via metabolite exchange.

Introduction

There is concern that antibiotic-resistance in bacteria may make commonly used antibiotics less effective. Oral immunotherapy (passive immunization) with specific antibodies is a strategy that has been actively pursued in laboratory and clinical studies for the last two decades. Feeding of egg yolk antibodies to neutralize specific pathogens, especially enteric microorganisms, is a potential alternative to antibiotics. Oral administration of these antibodies has met with some degree of success in prevention of viral and bacterial enteric infections in humans, piglets, calves, fish and rabbits. It is proposed that the egg yolk antibodies may act against enteric pathogens by binding, immobilising and consequently reducing or inhibiting the growth, replication, or colony forming abilities of these pathogens. Three immunoglobulin classes (IgA, IgM and IgY) have been shown to exist in chickens. Chicken immunoglobulin G (IgG) has been designated as immunoglobulin Y(IgY) because it varies in several aspects from mammalian IgG. IgY is the main serum immunoglobulin in chickens. It is transported from the hen to the embryo via the egg yolk. The egg yolk thus contains high concentrations of IgY. Other immunoglobulin (Ig) classes are present only in negligible amounts in the egg yolk. It has been shown that the presence of immunoglobulins in eggs is an example of passive immunity. This is because these antibodies originated from the hen and are used to protect the offspring from various infectious diseases after hatch.

Introduction

To improve the growth and health status, addition of antibiotics in the poultry feed was a common practice in last decade. Currently, in developed countries it is banned due to fatal consequences like development of antimicrobial resistant organism pool in the gut, persistence of antibiotic residue in the food chain that can reduce the food safety level. Therefore, various alternatives are now a day thought to use as poultry feed additives. Immunomodulaors are presently receiving wide attention as feed additives.

The term ‘immunomodulation’ is generally used to describe the manipulation of immune system which consists either increase (immunostimulation) or decrease (immunosuppression) in the magnitude of the immune system function. The chemicals or biological substances producing this phenomenon are known as ‘immunomodulators’. Specific immunomodulation involves the change in the immune response with a particular antigen (e.g. vaccination). Whereas, non-specific immunomodulation alters the immune response in such a way so that it become sensitive to a wide range of antigens. Generally this kind of non-specific immunomodulators are used as poultry feed additive to increase the resistance against the wide range of infections. The principal components of the immune system targeted for immunomodulation include T cells, B cells, monocytes, macrophages, granulocytes and natural killer cells (Dalloul and Lillehoj, 2005).

Introduction

An ionophore is a lipid-soluble molecule usually synthesized by microorganisms, which transport ions across cell membranes of susceptible bacteria, dissipating ion gradients and uncoupling energy expenditures from growth to kill these bacteria. The term ionophore was first used in 1967 for their ability of organic molecules to bind metal cations and form lipid soluble complexes that facilitate their transport across cell membrane. The ionophore antibiotics show wide varieties of biological activity ranging from antibacterial, antifungal, antimycoplasma, antiparasitic, antimalarial, antiviral, anti-inflammatory and tumourcell cytotoxic activity (Augustine, et al., 1987; Gumila et al., 1996). Presently seven polyether antibiotics include monensin, lasalocid, salinomycin, narasin, maduramycin, laidomycin and senduramycin are used around the world in various segments of cattle and poultry industries. These ionophores are mainly used as anticoccidial drugs in poultry and growth promoters in the ruminants. Polyether antibiotics are not used in human but recently, it has been shown that some of these compounds are able to selectively kill human cancer stem cells and multidrug resistant cancer cells. Hence, they are recognized as new potential anticancer drugs.

Introduction

After the discovery that low concentrations of antibiotics included in livestock diets had a beneficial effect on production efficiency, the use of antibiotic growth promoters (AGPs) became a common practice, benefiting both the livestock industry and consumers. Antibiotic growth promotion in agricultural and animal production has been practiced for about 50 years (Dibner et al., 2007). Orally ingested antibiotics promote growth and efficiency of poultry and other animals. Early indications of a beneficial effect on production efficiency in poultry and swine were reported by Moore et al. (1946) and Jukes et al. (1950).

Introduction

With the perception that antibiotics should no longer be used as animal growth promoters, there has been widespread interest in natural methods of inhibiting detrimental bacteria. Their removal from the poultry diets is therefore brings with it consequences. This has lead to somewhat of a renaissance in research activity on the discovery and application of non antibiotic chemical compounds capable of either killing microorganisms outright or at the very least retarding growth sufficiently to limit their dissemination. Organic acids have a long history of being utilized as food additives and preservatives for preventing food deterioration and extending the shelf life of perishable food ingredients. In recent past organic acids have been used to control microbial contamination and replace antibiotic growth promoters in poultry (Ricke, 2003; Hassan et al.,2010; Adil et al., 2011).

Introduction

Synbiotics refer to nutritional supplements combining probiotics and prebiotics in form of a synergism. The synbiotic concept was first introduced as “mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and implantation of health-promoting bacteria. Probiotics are live bacteria which are intended to colonize the large intestine and confer physiological health benefits to the host. A prebiotic is a food or dietary supplement product that enhances the activity of probiotics. Synbiotics are not drugs and the effects are due to changes in bacteria population or enhancement of activity of the bacteria. A synbiotic may contain fiber, but all fiber is not necessarily a synbiotic.

Using prebiotics and probiotics in combination is often described as synbiotic, but the United Nations Food & Agriculture Organization (FAO) recommends that the term “synbiotic” be used only if the net health benefit is synergistic. A synbiotic contains fiber such as fructose oligosaccharide, galactose oligosaccharide, etc. and is intended to stimulate the microflora in the large intestine. The combination of probiotics and prebiotics work separately in the small and large intestine, but synergistically increase the overall gut health. Prebiotic has shown to increase the population and/or function of the probiotic it is paired with, as the probiotic is an external species, whereas prebiotics stimulate the flora which is already present.

Introduction

Prebiotics are non-digestible food ingredient which beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of health-promoting bacteria in the intestinal tract, thus improving the host‘s microbial balance (Gibson and Roberfroid, 1995). Normally, prebiotics contain some type of a non-digestible carbohydrate fraction (Rehman et al., 2009). Almost 90% of oligosaccharides escape digestion in the small intestine and reach the colon where they selectively stimulate the growth and/or activity of beneficial bacteria like Bifidobacteria, Lactobacillus and Streptococcus, providing prebiotic properties (Stanton et al., 2003). These bacteria populate the gut filling any niches were pathogenic bacteria may attempt to take hold. This concept is better known as competitive exclusion. Prebiotics function by lowering the gut pH through lactic acid production, inhibiting/preventing colonization of pathogens, modifying metabolic activity of normal intestinal flora, and stimulation of the immune system (Doyle and Erickson, 2006). Studies have demonstrated that these bacteria reduce pathogenic bacteria like Salmonella spp., Clostridium diffile and Campylobacter spp. (Hopkins and Macfarlane, 2003; Stern et al. 2000), by diverse mechanisms including competitive exclusion of nutrients or adhesion sites to intestinal mucosa (Stern et al. 2000) and fatty acid of short chain production, like propionic and butyric acids, which modifies the acidic conditions and inhibits the growth of microorganisms that cause infections (Collins and Gibson, 1999).

Pankaj Kumar Singh and Chandramoni

Introduction

The term “probiotic” is derived from Greek and means pro: for and bios: life (for life) in contradiction to antibiotic which means: against life. The term probiotic was first introduced by Lilly and Stillwel (1965) to describe growth-promoting factors produced by microorganisms. Parker (1974) first specified designation “probiotic”. He defined probiotics as microorganisms or substances, which contribute to the balance of the intestinal micro flora. Crawford (1979) defined probiotics as a culture of specific living microorganisms, primarily Lactobacillus spp. that are implanted in the organism and ensure the rapid and effective establishment of a beneficial intestinal population. Fuller (1989) discussed the definition given by Parker (1974) and considered it too broad, as cultures, cells, and metabolites are also included in antibiotic preparations. He redefined “probiotic” as a live microbial feed additive, which beneficially affects the animal by improving its microbial balance. Havenaar et al. (1992) pointed out that the definition of “probiotic” made by Fuller (1989) was restricted to feed supplements, animals, and their intestinal tract. Therefore, they generalized Fuller’s definition of “probiotic” as a mono or mixed culture of living microorganisms, which beneficially affect the host by improving the properties of the indigenous micro-flora. Through 1989, United States Department of Agriculture (USDA) advised manufactures to use the term: “direct-fed microbial” (DFM) instead of “probiotic” (Miles and Bootwalla, 1991). The USFDA defined DFM as a source of live naturally occurring microorganisms, including bacteria, fungi, and yeast. Vanbelle et al. (1990) pointed out that most researchers considered “probiotic” for selected and concentrated viable counts of lactic acid bacteria. Koh et al. (1992) pointed out that as a biological product for newly hatched chicks a bacterial culture producing acetic acid could be used. Such a culture might be supplied to the chicks either through their drinking water or by the feed. For controlling the biological balance in the chicken’s intestinal tract different probiotics may be used. The US National Food Ingredient Association presented, probiotics (direct fed microbial) as a source of live naturally occurring microorganisms and this includes bacteria, fungi and yeast (Miles and Bootwalla, 1991). According to the currently adopted definition by FAO, probiotics are: “live microorganisms which when administered in adequate amounts confer a health benefit on the host” (FAO/WHO, 2001). More precisely, probiotics are live microorganisms of nonpathogenic and nontoxic in nature, which when administered through the digestive route, are favorable to the host’s health (Guillot, et al., 1998; Thomke and Elwinger, 1998,).

Introduction

During the intensive system of poultry production birds are exposed to several types of stresses. The birds can tolerate mild stress but when the stress is severe, there is imbalance between oxidants and antioxidants which lead to oxidative stress and lipid peroxidative damage of tissues, ultimately results in poor performance. Nutrition has a strong impact on oxidative stress. Insufficient intake of antioxidants, a high intake of prooxidants, or both may lead to oxidative stress. The detrimental effects of oxidation process can be prevented by addition of antioxidant compounds in the feed. Vitamin E, carotenoids and selenium (Se) are among important antioxidant components of poultry diets. It is important to understand the role of antioxidants in poultry nutrition in general and in production and reproduction in particular. The chapter, here in will discuss the stressors in poultry production, oxidative stress and possible alleviation through dietary antioxidant supplementation.

Introduction

The competition between human and livestock population for the existing animal and plant resources has been of great concern to the poultry nutritionists. Today the poultry industry has already challenged by the high price of the feed ingredients. Moreover in the next century there will be a shortage of conventional feed stuffs for use in poultry production. Efforts are on to look forward for the new feed resources and to evaluate them for their inclusion in the poultry ration. However many of the feed stuffs are characterized by the presence of certain incriminating factors. The incorporation of feed stuffs containing incriminating factors may adversely affect the performance of poultry. The nutritional strategy involving the use of feed enzymes offer immense potential to overcome the problems. The use of enzymes in feed mixtures of growing poultry particularly for young chicks has been the subject of much research activity in the recent decades. The interest in the feed enzymes is a reflection in changing the attitude of the society and the economic climate of the feed industry. It has been seen that approximately 187 million metric tons of cereal grains (FAO, 2011) and 26.02 million tons oil seeds as per the trade estimate for 2011-12 are produced in India which yield non starch polysaccharides (NSP) as a part of variety of products.

Introduction

Modern intensive livestock and poultry production has achieved phenomenal gains in the efficient and economical production of high quality and safe animal products and by-products. Furthermore, the overall performance of livestock can be increased by improving nutrients utilization, health status, fertility and efficiency of production. The use of feed additives has been an important part of achieving efficient livestock production. Feed additives are non-nutritive substances, preparations and micro-organisms that are added to animal feed to improve productive, reproductive and health performances. Any substance is considered as a feed additive when, not having a direct utilization as nutrient, is included at an optimum concentration in diet to exert a positive action over the animal health status or the dietary nutrient utilization. Hutjens (1991) defined feed additives as a group of substances that can cause a desired animal response in a non-nutrient role, such as pH shift, growth, or metabolic modifier. Feed additives are added deliberately to animal feed which may favourably influences characteristics of the animal feed, feed intake, gastro-intestinal flora, digestibility of the animal feeds, animal production, health, fertility and characteristics of animal products. Because of their chemical nature as active principles, additives are generally included in very small proportions in diet.

Introduction
India has vast animal genetic resources with a wide variety of indigenous farm animals including cattle. The cattle breeds have evolved over generations to adapt to the agro-climatic and socio-economic needs of the people. Domestic animal diversity is defined as the spectrum of genetic differences within each breed and across all breeds within each domestic animal species, together with the species differences; all of which are available for the sustainable intensification of food and agriculture production. The domestic animal diversity has evolved over millions of years through the processes of natural selection forming and stabilizing each of the species used in food and agriculture. Over the more recent millennia the interaction between environmental and human selection has led to the development of genetically distinct breeds. Selection processes, directed by both humans and the environment, together with the random sampling processes causing genetic populations to drift over generations, have accelerated the development of the diversity within species leading to the creation of distinct genetic differences amongst breeds.

Cattle Breeding Policies and Programmes in the Planning Process

It is necessary to see how the issues relating to Cattle Breeding have been dealt with in the successive Plan periods starting from the First Five Year Plan. It is seen that, while the issue of surplus cattle has been handled in different ways in the various Plan documents, some discussing this issue at great length and other remaining completely silent on the subject, other issues such as cattle development, genetic improvement and breeding etc., have also received varying degrees of emphasis in the different Plans. 

General Selection Procedures for Dairy Breeds
Selection of Dairy Cows
Selecting a calf in calf show, a cow in cattle show by judging is an art. A dairy farmer should build up his own herd by breeding his own herd. Following guidelines will beuseful for selection of a diary cow. Whenever an animal is purchased from cattle fair, it should be selected based upon its breed characters and milk producing.
History sheet or pedigree sheet which are generally maintained in organized farmsreveals the complete history of animal.The maximum yield by dairy cows are noticed during the first five lactations. So generally selection should be carried out during First or Second lactation and thattoo are month after calving.?Three successive complete milkings has to be done and an average of it will givea fair idea regarding production by a particular animal.
A cow should allow anybody to milk, and should be docile.?It is better to purchase the animals during the months of October and November.?Maximum yield is noticed till 90 days after calving.

Heterosis, hybrid vigor, or outbreeding enhancement, is the improved or increased function of any biological quality in a hybrid offspring. The adjective derived from heterosis is heterotic.Heterosis is the occurrence of a superior offspring from mixing the genetic contributions of its parents. These effects can be due to Mendelian or non-Mendelian inheritance.

The aim of mating systems are either to increase or decrease the homozygosity of the progeny compared with the parents or in some cases, to maintain the degree of homozygosity unchanged. This aim constitutes the basis of the following classification of mating systems:

Progeny testing in India was introduced in the late 1950’s the first sire index in our country was suggested by Krishnan (1956) which was, however, similar to the herdmate and contemporary comparison methods. Robertson and Rendel (1954) stated that an efficient method of sire evaluation should satisfy two conditions: 

Open nucleus breeding system is considered to be a best approach to bring genetic improvement in livestock. This system was first introduced New Zealand for faster genetic improvement of sheep. The milk recording under field condition is quite expensive.  Moreover, farmers are not under any obligation to retain the animal till the lactation is completed.  The generation interval is also very large as it takes about 6-7 year by the time complete record on progeny testing programmes in developing countries is available, so that the effective genetic improvement is small.  Use of best proven bull on the elite cow, which are best 5-10% of the cow for genetic improvement of the population. The net genetic gain in the herd considering the actual genetic improvement from various parents off spring path is around 0.7% per annum.  Considering these situation in develop countries it has been proposed that ‘nucleus’ herd be created where males from the best cows are obtained.  The nucleus herd would be open in the sense that the lowest yielding cows are culled every year and are replaced by procurement of that many high yielding cow from farmers herd.  The nucleus herds are utilized entirely for production of males for breeding purposes in the population.

An animal breeder usually interested in various economic traits and when wishes to improve them in the herd/flock, he has three general methods at his disposal. Tandom method, independent culling level method and  index selection method.

Tandom Method

It involves selection for one trait at a time and until it reaches at a satisfactory level, and then for a third trait etc. This method is applicable only when the different traits in question are entirely independent or positively genetically associated to each other. Its effectiveness decreases with the increase in number of traits. This method is least desirable of all the methods.