Animal Nutrition Research Research Articles

A survey of some in vitro methods used for animal nutrition research and extension work in Europe: the differences between the references and the truth

As animal nutritionists are generally very cautious about using chemical analysis only for defining nutritional needs for livestock and as in vivo experiments are long, costly and subject to animal welfare legislation, much emphasis is placed on various in vitro analyses which are often regarded as being very informative in the absence of in vivo data. In vitro analyses may be applied to dry- (DMD) and organic-matter (OMD) digestibility and crude protein (CP) degradability (DG) and may involve ‘live’ cultures such as rumen fluid or gastric juices or ‘dead’ extracts containing enzymes. As part of an EU-funded Concerted Action (see Acknowledgements), a survey of the methods adopted for in vitro determinations (in vitro OMD, in vitro DG) for ruminants, pigs and poultry is underway: this paper presents a progress report of the information received to date concerning ruminant methods.The participants in the Concerted Action were asked to provide details of the in vitro methods actually in use in their countries, with particular attention to the methods used by the so-called Feed Information Centres (i.e. Feed Evaluation Units) for routine analyses (i.e. not experimental work). The participants supplied details of modifications and/or references to methods and this information was collated and circulated for checking and comment.

Nutritional profile of Kuwaiti composite dishes: Proximate composition, phytates content and protein quality evaluation

The chemical composition and nutritional quality of 22 Kuwaiti composite dishes were investigated. On a fresh weight basis, the dishes contained 13.9–91.6% moisture, 0.93–18.1% protein (Nx6.25), 0.2–16.4% fat, 0.00–0.8% crude fiber, 0.8–4.6% ash, 4.5–73.86% carbohydrates (by difference), 165.6–1556.8 kJoules (39.6–372.1 kcal) and 0.014–0.37% phytates. The essential amino acids most deficient in the dishes were mostly tryptophan (18 dishes) or either lysine (one dish) or total sulphur amino acids (M + C, in one dish). The chemical scores ranged between 15–96 (FAO/WHO, 1989). The in‐vitro protein digestibility (IVPD) calculated protein efficiency ratio (C‐PER), and protein digestibility corrected amino acid score (PDCAAS) values, ranged between 73.4–90.0%, 0.6–2.91 and 0.13–0.84, respectively. Under identical conditions, the Animal Nutrition Research Council casein showed IVPD, C‐PER and PDCAAS values of 90%, 2.5 and 1.00 respectively. The significance of these results are discussed.

Use of naturally enriched mixed food in 13C breath tests applied in young suckling calves.

Utilization of three milk diets including cream, casein or whey, each naturally labelled with 13C (1 mmol 13C excess) from C4 sources, by six young male calves of the Deutsche Fleckvieh breed was investigated in a Latin-square split-plot design. Each milk diet was examined under resting conditions and during a short period of physical exercise on a treadmill. Delta 13C values (/1000) in carbon dioxide in expired air were measured at intervals of about 1 h during 6.5 h after food intake. Expired air samples for CO2 isolation, subsequent isotopic analysis, measurement of CO2 production and respiratory quotient were taken at about hourly intervals and 13C recovery rates over 6.5 h were calculated. Feeding milk containing enriched milk casein, cream, or whey resulted in maximal significant 13C enrichments over background (delta 13C) in CO2 of +1, +2.4 and +2.2 /1000, and recovery rates of 3.6, 9.9 and 12.2% respectively. This comparison shows the different kinetic behaviour of the main nutrients during the oxidation in tissues. The short exercise period (5 min at 1 J/s per kg body-weight +5 min at 2 J/s per kg body-weight) did not influence the recovery rates significantly. However, after 10 min of muscular exercise there was a brief decrease in delta 13C value of expired air which disappeared within the first 5 min of rest. These experiments demonstrate for the first time the applicability of the 13C breath test with naturally enriched diets in animal nutrition research and that quantitative results may be obtained.

Digestibility of Nitrogen and Amino Acids in Selected Protein Sources Fed to Mice

The purpose of this investigation was 1) to determine the apparent and true digestibilities in mice of nitrogen (N) and amino acids (AA) in commercially refined protein sources, and 2) to estimate metabolic fecal nitrogen (MFN) excretion. Each protein source was fed to adult female mice at 15 and 30% of a purified diet. A protein-free diet was included. Nutrient digestibility was determined by a fecal balance method with chromic oxide as a marker. Apparent digestibility of N in each protein source reflected the dietary N concentration and AA digestibility showed a similar trend. True digestibility (TD) of N was 97-98% for Animal Nutrition Research Council reference protein, casein, gelatin and gliadin, 94-96% for lactalbumin and soy protein and 81% for zein. TD of AA generally reflected TD of N. MFN excretion (g/100 g dry matter consumed) was 0.146 when the protein-free diet was fed and 0.151 by extrapolation to zero N intake. It was concluded that when commercially refined proteins are fed to mice, MFN excretion can be determined by either method, but this may not apply when the protein source contains antinutritive substances.

Nutritional evaluation of selected meat based Saudi Arabian dishes

Fourteen popular Saudi Arabian dishes containing a significant amount of animal protein (meat, fish, egg) were investigated. On a fresh weight basis, the dishes contained 46.6–82.6% moisture, 3.6–9.4% protein (N × 6.25), 0.7–14.7% fat, 0.1–1.1% crude fiber, 0.8–2.4% ash, 3.9–40.9% nitrogen free extract and 82–236 Cals 0.34–0.99 Mj) per 100 g food. The dishes had reasonably good amounts of K, P, Fe, Cu, Mn, and some B‐vitamins. Vitamin‐A, folacin and ascorbic acid content were generally present in lower amounts. Amino acid profiles were good when compared with that of FAO/WHO (1973) reference protein except for one dish (Motabak ma'moz), which had lower concentration of both lysine (2.8 g/16g N) and tryptophan (0.6g/16g N). The chemical score ranged from 70–100, except Motabak ma'moz, for which the chemical score was 51. Tryptophan was generally the first limiting essential amino acid except in two dishes where methionine + cystine or lysine were the first limiting essential amino acids. The in vitro protein digestibility values ranged between 80.6–90.3% in comparison to Animal Nutrition Research Council (ANRC) casein value of 90.0%. The calculated protein efficiency ratio varied between 1.51–3.06 when adjusted to ANRC casein value of 2.50.

Chemical and nutritional quality of some Saudi Arabian dishes based on cereals and legumes 1. Proximate composition, Amino Acid contents and nutritive value

Chemical composition and nutritional quality of six Saudi Arabian dishes based on cereals and/or legumes were investigated. On a fresh weight basis, the dishes contained 54.0–78.5 % moisture, 2.6–7.5% protein (N × 6.25), 0.5–4.9% fat, 0.1–1.8% crude fiber, 0.3–1.8% ash, 12.6–38.7% carbohydrates (by difference) and 386–811 KJ (92–193 Cals) per 100 g dish. The essential amino acids most deficient in the dishes were either tryptophan (in four dishes), or lysine (one dish) or total sulphur amino acids (methionine + cystine, in one dish). The chemical scores ranged between 26–67 (FAO/WHO, 1973). The in‐vitro protein digestibility (IVPD) and calculated protein efficiency ratio (C‐PER) values ranged between 77.9–88.9 % and 0.45–2.01, respectively. Under identical conditions, the Animal Nutrition Research Council casein showed IVPD and C‐PER values of 90.0 % and 2.50, respectively. The significance of these results are discussed.

Mineral X disease interactions.

The ability of animals to cope with infection may be influenced by mineral nutrition, in particular Mg and P of the macroelements and Zn, Fe, Cu and Se of the trace elements. Deficiencies of Zn, Fe, Cu and Se have resulted in a lowered resistance to disease either through an impaired immune response or faulty leukocyte function. The role of Se in bactericidal action of the phagocytes is associated with oxidative functions believed important for killing phagocytized bacteria. The role of these and other essential elements in disease prevention is an important area of animal nutrition research.

Chemical Composition and Nutritive Value of Truffles of Saudi Arabia

ABSTRACTThe chemical composition and nutritional quality of truffles of Saudi Arabia, Terfezia claveryi and Tirmania nivea, were studied. Results showed 19.6 and 27.2% protein, 2.8 and 7.4% fat, 7.0 and 13.2% crude fiber, 4.6 and 5.4% ash and 1.8 and 5.1% ascorbic acid for T. claveryi and T. nivea, respectively. Both varieties contained high amounts of K and P and fair levels of Fe, Cu, Zn and Mn. All essential amino acids were present in fairly good amounts. Leucine and lysine were the fist limiting amino acids in T. claveryi and valme in T. nivea. In‐vitro protein digestibility (82.8 ‐ 86.7%) was slightly lower than that of Animal Nutrition Research Council (ANRC) casein (90.0%) but the calculated protein efficiency ratio (2.1 ‐ 2.49) was relatively close to the value of 2.5 for ANRC casein.

A Collaborative Study to Evaluate a Precision-Fed Rooster Assay for True Amino Acid Availability in Feed Ingredients

A collaborative study involving six laboratories was undertaken by the US Animal Nutrition Research Council to evaluate a precision-fed rooster assay as a means of measuring biological availability of amino acids in a variety of feedstuffs for poultry. Despite differences in analytical and bioassay methodology, there was good agreement in true amino acid availability (TAAA) values between laboratories for the six different feed ingredients and two mixtures tested. However, considerable variation was reported in total amino acid values for identical and commonly used feed ingredients. The excellent agreement that existed between the TAAA values found for the mixtures of ingredients with those calculated from the data found for the components suggests that TAAA values are additive. The TAAA values from two sources of meat meals, which had widely different true metabolizable energy values without and with the nitrogen correction (TME and TMEn), demonstrate that differences in energy values should not be interpreted as an indication of differences in protein quality, because the TAAA values of these meat meals were nearly identical. Data from three different laboratories indicated that cystine in meat meal was less available than other amino acids. Recommendations for improvement and applicability of the assay are suggested, as are areas for future research.

Chemical composition and nutritional quality ofCleome dolichostyla seeds

Seeds ofCleome dolichostyla were analysed for proximate composition, mineral element contents and amino acid composition, in-vitro protein digestibility (IVPD) and calculated protein efficiency ratio (C-PER). The seeds (dry basis) were rich in oil (32.1%), protein (24.6%) and fiber (17.8%) content. The contents of various mineral elements mg/100 g) were: Ca=1970, P=493, Mg=127, Na=35, K=465, Fe=71.97, Zn=2.25, Cu=0.44 and Mn=1.45. Aspartic acid, glutamic acid, glycine, arginine and histidine were the major amino acids inC. dolichostyla seed protein accounting for half of the total amino acids. Lysine was the most limiting essential amino acid (FAO/WHO, 1973 reference pattern) with a chemical score of 45 for the protein. The IVPD of cleome seed protein was 72.2% and C-PER was 1.08 relative to the IVPD and C-PER values of 90.0% and 2.50 for the Animal Nutrition Research Council casein.

MACARONI ENRICHMENT WITH DAIRY‐BASED PROTEIN SOURCES

ABSTRACTCombinations of soluble and heat‐coagulated cheese whey proteins, of yeast grown on cheese whey and heat‐coagulated whey proteins, and Animal Nutrition Research Council (ANRC) casein alone were used to raise the protein content of conventional macaroni to 20%. All protein sources and combinations tested increased the Protein Efficiency. Ratio value of the macaroni to equal to or greater than that of casein. The yeast added a “bitter” flavor and a “sticky” texture. Varying the proportion of soluble and heat‐coagulated cheese whey proteins caused no changes in the flavor or texture of macaroni enriched with the heat‐coagulated proteins alone. Enrichment with ANRC casein had no effect on the flavor or texture of conventional macaroni.

Agriculture group symposium crop and animal nutrition research

AbstractThe following are summaries of papers presented at a symposium held at Jealott 's Hill Research Station on 19 October 1976. The reports so published are entirely the responsibility of the authors and in no way reflect the views of the Editorial Board of the Journal of the Science of Food and Agriculture.

Recent developments in animal nutrition research in Eastern Europe.

Recent developments in animal nutrition research in Eastern Europe.

Least-Cost Livestock Production Rations

Animal scientists and agricultural economists have been working together to answer the question, “What is the least-cost feed mix for a given set of prices?” In the 1950's sophisticated mathematical programming via computers generated a renewed interest in ration formulation. Since then, animal scientists and agricultural economists have been intrigued with determing least-cost rations for various livestock species. But this research has been devoted to determining the least-cost rations rather than minimizing feed cost per pound of gain or pound of product produced and/or minimizing total cost per pound of gain or product produced. Answering the latter question is a prime goal of animal nutrition research.

Current and future problems in animal nutrition research

Current and future problems in animal nutrition research

Research into foods from animal sources. I. Controlling level and type of fat

This review of research on the amount of fat and the fatty acid composition of the fat in meat and dairy products, primarily covering the research of the Agricultural Research Service, shows clearly that the agricultural producer can furnish the consumer what he wants, as has been done in the past. The lean meat of our best beef, pork, and poultry can be used at any desirable level in a mixed diet with 35% of total calories from fat. Fat content of dairy products is readily controlled by processing, as is done commercially now. Major changes in composition of fats of ruminants can be made by feeding “protected” polyunsaturated oils. The fatty acid composition of monogastric animals, hogs, chickens, turkeys, etc. can be readily controlled by the diet food. The cholesterol content of eggs can be experimentally reduced by dietary means, and perhaps by genetic changes. The usefulness of the results cited in making changes in the American food supply is not clear. What changes should be made, what changes can be made, will depend on further research in human and animal nutrition, economics, and social attitudes.

A comparison of some laboratory techniques for the estimation of the digestibility of the organic matter in forage samples.

The 194 samples of forage were of 6 groups; grass or other forage dried, fresh or ensiled. Workers from 5 institutes analysed some of the samples by their usual methods, 10 methods altogether. Digestibility estimated with sheep was regressed on the other results and correlation coefficients and residual standard deviations were calculated; those were closer for groups of forages than for all forages together. The least accurate predictor of digestibility in vivo was crude fibre content, which is much used in the Netherlands. The best method for each fodder group was the method of Tilley and Terry (NAR 34, 156) as modified by Koelen, Kemmink and Dijkstra (De bepaling van de voederwaarde van ruwvoeders met behulp van de in vitroverteerbaarheid. Internal Report, Institute for Animal Feeding and Nutrition Research 'Hoorn' (1969), No. 27, available in English). It took least work but required sheep rumen fluid. For all groups together, the cell-wall constituents method of Gaillard and Nijkamp (NAR 38, 8034) was better for 54 samples but the residual standard deviation was higher than within groups; it required more labour, but not rumen fluid. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Evaluation Studies on the Animal Nutrition Research Council Vitamin E Reference Standard in Chickens

INTRODUCTIONTHE Animal Nutrition Research Council (A.N.R.C.) Vitamin E Reference Standard1 is a dry, free-flowing, gelatin beadlet containing 50 I.U. of stabilized vitamin E/g. in the form of dl-α-tocopheryl acetate. It was adopted as the A.N.R.C. Reference Standard in 1962 after extensive biological evaluation by Pudelkiewicz (1959), Matterson and Dicks (1960) and Matterson (1961). Marusich et al. (1964) and Matterson (1964), in meeting presentations, reported on the biological performance and physical characteristic data available at that time. The A.N.R.C. Vitamin E Reference Standard is intended to aid biological research, routine potency testing of products and general inter-laboratory collaborative studies by providing a convenient, uniform and stable source of vitamin E activity.The purpose of this paper is to present further data obtained with the A.N.R.C. Standard in our laboratory. Both biological and chemical stability data have been included. Uniformity of response based on plasma and liver levels of vitamin E…

Application of findings of research in animal nutrition to man.

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Data from recent research in animal nutrition, important for breeders of fodder plants

Preliminary investigations as to the practical influence of increased protein content in barley on the nutritional value of concentrates supplied for pig feeding, indicate that this influence is not very important.