eChapters

It is very essential to know the nutritive value of common feedstuffs used in the diet of ruminants. On the basis of these values the nutrient requirements of ruminants may be fulfilled for different body functions like maintenance, growth, lactation, wool production or others. The nutritive value of various common feedstuffs used in the diet of ruminants is being presented in the table below:

The nutritive value of feedstuffs is generally expressed in terms of protein and energy value. The protein and energy value usually referred in ruminants are DCP (Digestible crude protein) and TDN (Total digestible nutrients), because the feeds used in the diet of ruminants have a vide variability in their digestibility, hence after removal of the variable fraction the requirement of nutrients is expressed. Starch Equivalent (SE) is also the measure of energy but its usefulness is limited to certain extent, due to involvement of tedious and expensive process.

Digestion trial requires feaces collection only but when we have to go for balance studies we have to collect urine also (in addition to the nutrient losses take place through milk in lactating animals) to find out the nutrient losses takes place through urine. As we have discussed in digestion trial also, male animals are usually preferred to perform these types of studies to obtain contamination free urine and feaces to find out clear picture.

Balance studies are usually performed to find out the balance of nitrogen (Nitrogen retention, NR) and minerals (Ca, P etc.) as urine is rich in these nutrients and hence for their balance we have to find out the losses takes place through urine.

Proximate analysis of the feeds and fodders does not give any idea about their nutritive value, because availability of nutrients varies according to the feed stuffs. The major loss of nutrients take place in body after ingestion of feed is through feces. Hence, it is very essential to know the actual amount of feed digested by the animals. Losses which take place after digestion are more or less comparable in different feedstuffs.

Digestibility
Digestibility of a feed can be defined as that proportion of feed which is not being excreted in the faeces and hence assumed to be absorbed by the animal. It is expressed as percentage (% digestibility or digestibility coefficient).

Silage is the green material produced by controlled anaerobic fermentation of the green succulent fodder crop retaining its moisture content. The process of preparing silage is known as Ensiling and the pit in which silage is prepared is called silo.

Crops suitable for silage making
The fundamental behind the conservation of fodder as silage is the acidic condition, which is produced by the anaerobic fermentation of carbohydrates rich fodder. Thus the necessity of the fodder crop being used for silage preparation is the presence of high amount of fermentable carbohydrates and the natural carbohydrate rich crops are the cereal crops like maize, jowar or bajra and grasses or their combination in 3:1 with leguminous crops. Otherwise high moisture leguminous crop after wilting in combination of molasses may be 
used.

To overcome the limitation of proximate analysis P.J. Van Soest in 1963 developed a method which makes use of the concept that the dry matter of plant origin consists of two principal parts:
    1.    Cell contents 
    2.    Cell wall contents

The method is efficient to take care of the defects in the principle of estimating crude fiber and NFE by proximate analysis. Van Soest has partitioned the carbohydrates into various fractions by a system of analysis using detergents. Cell contents are soluble in neutral detergent includes lipids, sugars, organic acids, starch, soluble proteins, NPN compounds and other water soluble materials, where as cell wall (fiber) is insoluble in neutral detergent but it is soluble in acid detergent includes hemicelluloses, cellulose, lignin, lignified nitrogen compounds, heat damages proteins, keratins and silica. This method of partitioning carbohydrate is essential to be expressed in case of ruminants, due to their capacities for making use of different fractions of crude fibre especially the cellulose and hemicellulose, while the simple stomached animals can rarely do so. 

Principle

Phosphorus is the chief acid forming mineral constituent of plant and feeds. Phosphorus present in the ash solution (Mineral extract) is precipitated as ammonium phosphomolybedate. The precipitate is washed with dilute potassium nitrate till free from acid and dissolved in a known excess of standard sodium hydroxide solution. The excess alkali is back titrated against standard acid to arrive at the exact quantity of standard solution required.

Principle

When a solution containing calcium is treated with ammonium oxalate, all the calcium present is precipitated as calcium oxalate. The precipitate when dissolves in sulphuric acid, forming calcium sulphate and liberating free oxalic acid which is quantitatively estimated by titration against standard N/10 KMnO₄ to arrive at the calcium content present in the given solution. Following chemical reactions takes place in the estimation of calcium:

Principle

Carbohydrates are divided into two groups i.e., crude fibre (CF) and nitrogen free extractives (NFE). The NFE comprises the sugars, starch and a large part of the material classed as hemicellulose.

The NFE is not determined by analytical procedures. This is calculated as the figure obtained when the sum of water, ash, protein, fat and crude fibre of a feed is subtracted from 100. Since the figure is determined by difference, it includes the cumulative errors of the other determinations and thus it is not an exact value.

Requirement

Following analysed volumes of a feedstuff are very much essential to derive the nitrogen free extractives of the same feedstuff.

Calculation
The nitrogen free extractives can be derived from the following formula:

Principle

When a sample of moisture and fat free feedstuff is boiled with dilute acid and then with dilute alkali, the soluble carbohydrates and proteins go into the solution and are extracted. The undissolved residue left behind represents cellulose, hemicellulose, lignin and mineral matter. The cellulose, hemicellulose and lignin put together are called crude fibre (CF). When the residue after drying and weighing is ignited, the fibre being organic in nature is burnt whereas the ash or mineral matter is left over. The fibre is obtained by deducting the weight of ash from the weight of the dried residue. In simple way it can also be explained that the crude fibre is determined gravimetrically as part of the substance which is left when protein, soluble carbohydrate, fat, ash and water have been removed.

In feeding of simple stomached animals, the analysis of crude fibre content is very essential because the amount of crude fibre predicts the digestibility of the feedstuff. Higher the fibre content lesser will be the digestibility.

Principle
When a sample of feed, which is free from moisture, is extracted continuously with fat solvent like petroleum ether, the vapour from the ether boiling in the flask passes into the condenser where it condenses and drops back on the sample which dissolves ether soluble materials such as fat, sterols, lecithin, resins and volatile oils in the extraction flask. The extract is termed as crude fat or ether extract (EE) because it also contains other fat like substances in addition to true fat.

Equipment/glass wares
    1.     Analytical balance
    2.     Beaker
    3.     Cotton wool
    4.     Dessicator
    5.     Extraction thimble
    6.     Hot air oven
    7.     Oil flask (150-250 ml)

Principle

Crude protein constitutes a mixture of true protein and non protein nitrogenous substances and is determined by estimating nitrogen and then multiplying the nitrogen content of feed by the factor 6.25.

The factor 6.25 is derived on the basis that all proteins contain 16% nitrogen. The total nitrogen content in the feedstuff is determined by Kjeldahl method which generally consists of three steps, i.e. digestion, distillation and titration. The sample is digested with an excess quantity of concentrated sulphuric acid which hydrolyses the protein, decomposes to ammonia and finally the ammonia combines with the excess of sulphuric acid forming ammonium sulphate. The acid digest is cooled, diluted with distilled water and distilled with strong alkali (sodium hydroxide, 40 per cent), the ammonia released during distillation is taken up into a boric acid solution forming ammonium borate complex and such ammonia is titrated with standard sulphuric acid. While estimating the nitrogen content, following reactions take place:

Principle

The portion of the total ash which is insoluble in dilute hydrochloric acid is called acid insoluble ash (AlA) and it is the part of ash which is having unavailable mineral matter like silica and sand. Silica is the part of mature plant materials which are highly lignified or woody like straw, husk, stems and stalks, while sand inters in feeds by faulty handling in the fields or as an adulterant.

Equipment/glass wares
    1.    Asbestos sheet
    2.     Filter paper (Whatman No.1)
    3.    Funnel stand
    4.    Glass funnel
    5.     Glass rod
    6.     Hot plate/heater/Bunsen flame
    7.     Metal tongs
    8.     Silica basin (crucible)
    9.     Volumetric flask
    10.     Wash bottle with distilled water

Principle
Total ash is the inorganic residue which remains after a feed stuff is ignited to carbon free at 550-600oC in a muffle furnace. In other words, ash is that part of the material which does not disappear at 550-600ºC, while all the organic matter (OM) gets burnet.

Requirement
    1.    Analytical balance
    2.     Asbestos sheet
    3.     Dessicator
    4.     Heater /gas flame burner
    5.     Metal tongs
    6.     Muffle furnace
    7.     Silica basin/crucibles

Principle
If a sample of feed is heated and dried in a hot air oven at the temperature of boiling water (100°C ± 2°C), the water present in feed sample escapes as vapour. The loss in weight is considered as moisture and the residue is termed as dry matter (DM).

Requirement
    1.    Aluminium/steel moisture cup or Iron trey
    2.     Analytical balance
    3.     Dessicator
    4.     Hot air oven
    5.     Metal tongs
    6.     Spatula

Two German scientists Henneberg and Stohmann working at the Weende Experimental Station, Germany devised proximate principles analysis system in 1860’s for routine description of animal feedstuffs. Therefore this system is also known as Weende system of analysis. Proximate analysis is a system of expressing the nutrient composition of a feed. The principle of analysis is to separate the nutrient present in the feedstuffs into various fractions, as proximate principles, which are six i.e. moisture, ash, crude protein, ether extract, crude fibre and nitrogen free extract.

Water (Moisture)

The moisture is determined as the loss in weight which results from drying a known weight of feed to constant weight at 100°C. Therefore, dry matter is estimated as a part of substance that does not evaporate at 100°C. The major difference in nutritional value on as fed basis is traceable to moisture content and dry matter. Calculation of relative cost of nutritional value involves consideration of moisture content.

The procedure used in the preparation of samples depends on the purpose of analysis and the nature of the constituents that are to be determined.

a. Plant material (Herbage)

    1.    Separate the plant material by using sharp knife.
    2.    Remove the contaminations like soil or other material by gentle brushing. Never wash the plant material with water.
    3.    Mix corresponding plant parts from more than one plant to obtain representative sample of sufficient size for analysis.
    4.    Cut the sample immediately into small pieces and mix thoroughly. 
    5.    Weigh a portion of this sample for those analyses which are to be performed on green material. 
    6.    Dry the sample in a hot air oven at 100 ± 2ºC for storage.

Livestock feeds are generally classified according to the amount of a specific nutrient they furnish in the ration. They are divided into two general classes roughages and concentrates. Roughages are bulky feeds containing relatively large amount of less digestible material, i.e. crude fiber more than 18% and lower than 60% TDN on dry matter basis. Concentrates are feeds which contain relatively smaller amount (less than 18%) of fiber and have comparatively high digestibility and as a result higher nutritive value having more than 60% TDN.

A. Roughages

Roughages are subdivided into two major groups – succulent and dry, based upon the moisture content. Succulent feeds usually contain moisture content from 60 to 90%, whereas dry contains only 10 to 15% moisture. Succulent may again be divided into pasture, cultivated fodder crops, tree leaves, silage and root crops. Dry roughages may be further classified as hay and straw based on the nutritive value and methods of preservation.

1. Introduction

Phytochemicals are biologically active compounds found in plants, which act as a resistance system for host plants and protect them from biotic and abiotic stresses. Phytochemicals act as antioxidants, which react with the free radicals present in the cell. Free radicals are formed in the cell as a result of aerobic metabolism and these radicals are biologically active that damages the macromolecules like DNA, proteins and lipids resulting in oxidizing chain reactions (Moussa et al., 2011). Oxidative stress damage leads to various disorders like autoimmune disorders, cancer, rheumatoid arthritis, cataract, aging, cardiovascular diseases and other neurodegenerative disorders (Uttara et al., 2009). The major actions of antioxidant in the cells are to protect them against the damage caused by reactive oxygen species (ROS).

Medicinal plants are good sources of antioxidants such as vitamin E, ascorbic acid and carotenoids. There are huge numbers of medicinal plants that are veiled in the environment. In ancient times, different plant species have been used for the treatment of human ailments from fever to cancer (Devendrakumar et al., 2009).

1. Introduction

Plant-derived substances have recently become of great interest owing to their versatile applications. Medicinal plants are the richest bio-resource of drugs of traditional systems of medicine, modern medicines, nutraceuticals, food supplements, folk medicines, pharmaceutical intermediates and  chemical entities for synthetic drugs Medicinal value lies in certain chemical substances that have its physiological action on the human body. Many indigenous medicinal plants are used as spices and food plants. The general techniques of medicinal plant extraction include maceration, infusion, percolation, digestion, decoction, hot continuous extraction (Soxhlet), aqueous-alcoholic extraction by fermentation,  counter-current extraction, microwave-assisted extraction, ultrasound extraction (sonication), supercritical fluid extraction, and phytonic extraction (with hydrofluorocarbon solvents). For aromatic plants, hydrodistillation techniques (water distillation, steam distillation, water and steam distillation), hydrolytic  maceration followed by distillation, expression and enfleurage (cold fat extraction) may be employed.