Proximate analysis.pptx

Proximate analysis.pptx

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  Agriculture University, Jodhpur 1 Topic: Proximate principlesof feed by Dr. Rashmi Bhinda Assistant Professor (Animal Production) College of Agriculture, Jodhpur (Agriculture University, Jodhpur)
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  Agriculture University, Jodhpur 2 What is aProximate ?  A method for the quantitative analysis of the different macronutrients in feed.  It is the Weende or proximate analysis, Chemical analysis of feed and fodders.  Developed in 1865 by Henneberg and Stohmann.  At weende experimental station in Germany. Components Proximate Analysis is a partitioning of compounds in a feed into six categories based on the chemical properties of the compounds. The six categories are: 1. Moisture 2. Crude protein (CP) 3. Crude fibre (CF) 4. Nitrogen-free extracts (NFE, digestible carbohydrates) 5. Ether extract (EE) 6. Total Ash
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  Agriculture University, Jodhpur 3 Moisture: It representsthe water content of feedstuff. The portion of feedstuff other than moisture is called as dry matter (DM). Crude protein (CP): It represents the total amount of Protein in the feedstuff. The crude protein include true protein as well as non-protein nitrogenous substance like urea, biuret, and amides. Crude protein is determined by measuring the nitrogen content of the feed and multiplying it by a factor of 6.25. This factor is based on the fact that most protein contains 16% nitrogen. Crude protein is determined by kjeldahl method. The method involves: Digestion, Distillation and Titration. Crude fibre: it includes less digestible carbohydrates like pectins, cellulose, and hemicellulose and non-carbohydrate fraction like lignin. Nitrogen-free extracts (NFE): It includes more digestible carbohydrates like starch sugars and also cellulose and hemicellulose in minor quantity. Ether extract: it represents liquid portion of feedstuff. Thus it contains fats, fatty acids, pigments, waxes etc. Total Ash: It represents inorganic portion of feedstuff like minerals and silica.
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  Agriculture University, Jodhpur 4 Feed sample analysismethod
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  5 Agriculture University, Jodhpur Principle If a sampleof feed is heated and dried in a hot air oven at the temperature of boiling water (100°C ± 5 °C) for 12-18 hours , 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). (W1 - W2) Moisture (%) = ---------------------------------------------X100 W1-W Where, W = wt. of moisture cup W1 = wt. of moisture cup + sample W2 = wt. of moisture cup + sample after drying Dry matter (%) = 100 – Moisture (%) Requirement 1. Aluminium moisture cup, 2. Analytical balance, 3. desiccator, 4. Hot air oven, 5. Metal tongs 6. spatula Determination of Dry matter
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  6 Agriculture University, Jodhpur It is estimatedby micro-Kjeldahl method. 2-3 g samples take and digest in the Kjeldahl flask with 20-30 ml of concentrated H2SO4 in presence of 3g digestion mixture (potassium sulphate and copper sulphate in the ratio of 9:1). After completion of digestion, the content are cool and transfers to a 100 ml volumetric flask and volume make-up with distilled water. An aliquot (10 ml) is transfers to micro-Kjeldahl assembly; sufficient amount of 40% NaOH is added to make contents alkaline. The distillate collected in a 100 ml flask containing 20 ml 2% Boric acid (with mixed indicator, Methyl red + Bromocerol green in the ratio 2:1 added up to cherry colour developed). The distillate titrates against 0.01N H2SO4. The quantity of nitrogen estimates, on the basis of fact that 1.0 ml of standard 0.01N H2SO4 is equivalent to 0.00014 g nitrogen. Crude protein estimation
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  7 Agriculture University, Jodhpur 140 xV x n Nitrogen (per cent) = ———————— on moisture free basis m (100-M) where, V = volume in ml of the standard H2SO4 used n = normality of the standard used H2SO4 used m = sample weight in g M = moisture percentage For conversion on nitrogen into crude protein where, CP (%) = n (%) x 6.25 CP= crude protein (%) content of feedstuff n = total nitrogen (%) present in feedstuff Organic nitrogen + H2SO4 -------------------------- (NH4)2SO4 (During digestion) (NH4)2SO4 + 2NaOH -------------------Na2SO4 + 2NH3 + 2H2O (During distillation) 2NH3 + H2SO4 (Standard) --------------------------- (NH4)2SO4 (during titration)
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  9 Agriculture University, Jodhpur Total fat/ etherextract Principle When a sample of feed 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, lecithins, 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. It is analyzed with the help of Soxhlet’s apparatus. Two gram dried and ground feed sample was placed to in a weighed extraction thimble. Petroleum ether (60-80⁰C) continuously volatilized (8-10 hrs), condensed and allowed pass through the samples in a Soxhlet’s apparatus. The loss in weight of the sample as the result of the ether treatment takes as the measure of the total fat.
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  Formula for EtherExtract 10 100 (w1 – w2) 100 x wt of ether extract Ether extract, per cent on as such basis = ———————— or ———————— m wt. of sample where, w1 = wt. in g of oil flask + extracted material w2 = wt. in g of empty oil flask m = wt. in g of sample If the thimble with sample has not been dried in hot air oven at 80-100°C for 10-12 hours prior to extraction, the crude fat (ether extract) value can be converted into dry matter basis. Crude fat x dry matter per cent Ether extract on DM basis = ——————————————— 100 N.B.-The digestible ether extract is multiplied by 2.25 because on oxidation fat provides 2.25 times more energy as compared to carbohydrates.
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  11 Agriculture University, Jodhpur Crude fiber When asample of moisture and fat free feedstuff is boiled with dilute acid followed by 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. obtained by deducting the weight of ash from the weight of the dried residue. In poultry feeding, 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. The fibre content is A-B Crude fiber content (%) = ------------- x100 C Where, A= weight of crucible with dry residue (g) B= weight of crucible with ash (g) C= weight of sample (g)
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  13 Agriculture University, Jodhpur Total ash Principle Totalash (TA) is the inorganic residue which remains after a feed stuff is ignited to carbon free at 550-600°C in a muffle furnace for four hours (AOAC, 2000). The previously recorded empty crucible weight was subtracted from the weight of crucible and its contents after ignition to determine weight of ash and expressed as percent of the dried sample. Calculation of Nitrogen-Free Extract (NFE) NFE (%) =100 – (CP% + CF% + EE% + Total ash) Where, CP = Crude protein CF = Crude fibre EE = Ether extract.
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  14 Agriculture University, Jodhpur Total DigestibleNutrients (TDN) A term used in animal feeding that designates the sum of all the digestible organic nutrients. (Digestible fat is multiplied by 2.25 because of its higher energy content) TDN is a feed is the sum of the digestible crude protein, digestible crude fibre, digestible nitrogen free extract and 2.25 times digestible ether extract. TDN requirements are given as Kilograms (Kg.). TDN is a way of expressing the energy content of feed. The TDN is calculated by the following formula: - TDN = DCP + DCF + DNFE + DEE X 2.25 Where, TDN = Total digestible nutrients (kg.) DCP = Digestible crude protein DCF = Digestible crude fibre DNFE = Digestible nitrogen free extract DEE = Digestible ether extract
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