Feed evaluation. PBMT 3: Pengujian Mutu Pakan

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1 Feed evaluation PBMT 3: Pengujian Mutu Pakan Anuraga Jayanegara A.Physical methods--> bulk density, sensory (organoleptic) analysis B. Chemical methods--> proxymate analysis, Van Soest s analysis, energy, protein quality (chemical score, essential amino acid index) C. Biological methods--> in vitrofermentation systems, in vivo feeding trials A. Physical methods Bulk Density Metode Fisik Metode Kimia Metode Biologi Sampel Mudah Dilakukan Lebih Akurat Lebih Akurat Kurang Akurat Membutuhkan Waktu dan Biaya Membutuhkan Waktu dan Biaya Lakukan Penimbangan terhadap Contoh Uji Organoleptik, Rapid Test Analisa Proksimat, Van Soest, Rapid Test Uji Kecernaan Gelas Ukur 1000 ml Hitung Berat Contoh dalam Gram per Liter ( Triplo ) Hubungan bulk density dengan kualitas pakan (Giger-Reverdin, 2000)

2 UJI ORGANOLEPTIK/SENSORI UJI ORGANOLEPTIK Tangan, Mata, Hidung, Lidah Tekstur Warna Bau Rasa Contoh: - Jagung: keberadaan jamur dan potensi kontaminasi mikotoksin --> warna - Dedak padi, minyak/lemak: bau tengik atau tidak - Silase: bau busuk (butirat, amonia, senyawa flavor lain) --> bau - Leguminosa: deteksi keberadaan tanin (suatu zat antinutrisi) melalui rasa pahit --> rasa - Rumput: menduga kualitas rerumputan melalui teksturnya (protein vs serat) --> tekstur B. Chemical methods Nutritive Value of Feed Analisis proksimat Proximate (Weende) system of analysis, Henneberg & Stohmann 1862 Fraction Nutritional Availability Monogastric Ruminant Sugars, Starch Complete Complete Protein High High Lipids High High Pectin High Complete Hemicellulose Low Partial Cellulose Low Partial Lignin / Cutin Indigestible Indigestible (adapted from Van Soest, 1966 and 1967) Feedstuff (FS) Drying 4h, 103 C Water content Substrate (DM) Kjeldahl Acid hydrolysis NH 3 distillation Ether extraction Hot acid and base 500 C (estimated by mass difference) Crude protein (XP) CP=N x 6.25 Crude lipid (XL) Crude fibre (XF) Crude ash (XA) OM=DM-XA Nitrogen free extract (NFE, XX)

3 Analisa air: Menggunakan oven dengan temperatur sedikit di atas temperatur didih air, misalnya 105 o C. Analisa abu: Abu adalah bagian dari sisa pembakaran dalam tanur dengan temperatur o C yang terdiri atas zat-zat anorganik atau mineral. Analisa protein kasar: Protein kasar adalah semua zat yang mengandung nitrogen. Dalam protein rata-rata mengandung nitrogen 16%. Metode yang sering digunakan dalam analisa protein adalah metode Kjeldahl yang melalui proses destruksi, destilasi, titrasi dan perhitungan. Analisa lemak kasar: Metode ekstraksi soxhlet dengan pelarut organik seperti petroleum ether. Analisa serat kasar: Fraksi dari karbohidrat yang tidak larut dalam basa dan asam encer setelah pendidihan masing-masing 30 menit. Bahan ekstrak tanpa nitrogen (Beta-N): Merupakan fraksi karbohidrat yang umumnya mudah tercerna antara lain pati dan gula.

4 Analisis serat Van Soest: Detergent Fibre System Crude protein (XP) Crude lipid (XL) protein, amino acids, ammonium compound, amides od acides, nitrogenous glycosides, B vitamins fats, oils, waxes, organic acids, pigments, sterols, vitamins A, D, E, K Cellulose Hemicellulose β-1,4-glucan, cellobiose + residues, forms microfibrils by intra-molecular and inter-molecular H-bonds, mechanical strength, highly crystalline or amorphous regions ( Cross-linking glycans ), diverse group of carbohydrates, common xyloglucans and glucuronarabinoxylans, soluble in strong alkali, β-1,4 backbone + short side chains, form H-bonds with cellulose Crude fibre (XF) cellulose, hemicellulose, lignin Pectin (pectic polysaccharides), easiest to remove from wall (hot water, dilute acid), form gels, function: determining wall porosity, providing charged wall surface for cell-cell adhesion, cell-cell recognition, pathogen recognition etc. Crude ash (XA) macro- and microminerals Protein glycoproteins (polypeptide backbone + carbohydrate side chains), cross-linked to pectic substances, may have sites for lignification, extraction requires destructive conditions, function: structural role, cell signalling (growth and guidance of pollen tube) Nitrogen free extract (NFE, XX) starch, sugars, fructosans, hemicellulose, pectin, organic acids, resins, tannins, pigments, water soluble vitamins Lignin Lipids Lignin: Polymer of phenolics, esp. phenylpropanoids, strengthening agent, resists fungal/pathogen attack Suberin, wax, cutin: variety of associated lipids for strength and waterproofing Van Soest 1964 Substrate (DM) Neutral detergent fibre Neutral detergent solution Hemicellulose, Cellulose, Lignin, Ash Acid detergent solution Soluble Protein, Lipids, Pectin Hemicellulose Digestiblity Acid detergent fibre Cellulose, Lignin, insoluble Ash 72% H 2 SO 4 Cellulose Acid detergent lignin Lignin, insoluble Ash 500 C Lignin insoluble Ash

5 Comparison of Detergent & Proximate System Detergent system Nitrogenous Non-nitrogenous Proximate system NPN compounds, proteins CP ND soluble (cell contents) lipids, ether soluble substances CL water soluble substances, pectins, starch AD soluble insoluble proteins hemicellulose NFE ND insoluble (cell wall) (NDF) AD insoluble (ADF) H 2 SO 4 soluble lignified proteins alkali soluble lignin cellulose H 2 SO 4 insoluble insoluble lignin (ADL) CF Other Methods to Determine Nutrient Contents Energy: Maintenance and Production Starch/ Enzymatic: Degradation and quantification of glucose/sugar Cell wall monomers (degradability of different sources, solubilisation) Refractometer: Estimation of the concentration of a starch solution by its refraction index (solubility, co-extractions) Growth MJ/kg Cattle 34 Calf 15 Pigs 26 Lactation MJ/kg Cattle 5.3 Calf -- Pigs 7.3 Reproduction MJ/kg Cattle 25 Calf -- Pigs 15 Protein Colorimetric assays: (Bradford, Neuhoff) reaction of protein with dyes relative to standard (different staining, extractability) Amino acid composition: Hydrolysis and quantification of AA by mass spectrometry (expensive, time consuming) Maintenance MJ/ kg 0.75 Cattle 0.48 Calf 0.52 Pigs 0.44 Lipids Chromatography: Extraction and quantification by HPLC (extractability, oxidation, quantification) Fasting metabolism Maintenance requirements

6 Energy Content of the Main Nutrients Determination of energy requirements Energy content (MJ/kg) Source gross physiological Polysaccharides (starch) Fat (triglycerides) Protein Gross energy tible energy Digest Me etabolisable energy tabolic Heat loss due to energy conversion Basal met rate Protein gain Fat depos sit Milk energ gy (protein, fat) Urine and Gas energy Energy in foetus, placenta Lebih lanjut tentang analisa energi DE = GE - E F ME = DE - (E u + E g ) Faecal energy IME = ME m * W ME pf * W + ME c * Wc + ME l * L (+ ME o * n o ) Next: C. Biological methods (in vitroand in vivo techniques) Thank you for your attention! Tawazun itu optimum

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