Agricultural Wastes 13 (1985) 155-158

Short Communication

Nylon-Bag Dry-Matter Digestibility in Agroindustrial By-products and Wastes of the Tropics

ABSTRACT

Twenty-eight samples oJagroindustrial by-products and wastes important in the tropics were studied for nylon-bag dry-matter digestibility. Among the samples studied, dehydrated culled pea had maximum nylon-bag dry- matter digestibility (79.40 %) while rice husk and poultry litter had the minimum (23.23% and 24.00%, respectively). It is not possible to compute a balanced maintenance diet for ruminants based solely on rice husk and poultry litter because of the low nylon-bag digestibilities.

I N T R O D U C T I O N

At present no published information related to the nylon-bag dry-matter digestibility of samples of agroindustrial by-products and wastes from the tropics is available. Such information may be used for selecting ingredients for computing a balanced ration. Because of the importance of this topic in livestock nutrition, the present investigation was undertaken to study the nylon-bag dry-matter digestibility of agro- industrial byproducts and wastes commonly fed to ruminants.

METHODS

Twenty-eight samples of commonly used agroindustrial by-products and wastes were collected, ground and sieved through a 1 mm sieve and stored

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T A B L E 1 Nylon-bag Dry-matter Digestibilities of Agroindustrial By-products and Wastes

(dry matter basis)

Local name Botanical name Nylon-bag dry-matter digestibility

(J/o)

1. Cereal and pulse byproducts Barley bran Maize gluten meal Maize husk (wet) Rice husk Rice (broken pieces) Pigeon pea husk Clusterbean meal (toasted) Black gram chuni

Hordeum t'ulgare Zea mays Zea mays Oryza satit'a Oryza satira Cajanus cajan Cyamopsis tetragonoloba Phaseolus mungo L.

42.90 64.11 50.10 23.23 28.62 46.37 68.97 59.95

2. Distillery byproducts Brewers grain Malt sprout with hulls

Hordeum t'ulgare Hordeum t'ulgare

46.00 66.66

3. Oil seed byproducts Cottonseed cake (undecorticated) Groundnut husk Mustard cake (ghani)

Gossypium hirsutum A rachis hypogaea Brassica compestris

59.58 29.61 77.64

4. Sugar industry bypoducts Sugarcane bagasse Sugarbeet pulp

Saccharum officinarum Beta t'ulgaris

52.31 45.04

5. Textile industry wastes Cottonseed hulls Gossypium sp. Cotton ginning trash Gossypium sp.

6. Vegetable and fruit preservation industry byproducts Dehydrated culled pea Pisum satirum Grape residue (winery pomace) Vitis rinifi, ra L.

29.90 35.29

79.40 37.35

7. Vegetable crop residues Bitter gourd leaves Carrot tops Hyacinth bean leaves Okra plant residue Potato haulm Spinach leaves Tomato leaves

Momordica charantia Oaucus carota Dolichos lablab Hibiscus escuh'ntus Solanum tuberosum Spinacea oleracea Lycopersieon escuh,ntum

62"09 63.92 50.15 40.73 54.06 53.55 45.78

8. Miscellaneous Cotton plant residue Poultry litter

Gossypium sp. 43.34 24.00

Digestibilities in agroindustrial by-products and wastes of the tropics 157

in sealed containers. Each sample was taken in triplicate for studying nylon-bag dry-matter digestibility by the standard method (Mehrez & Orskov, 1977). Nylon bags with mesh size of 20-40 #m, giving pore sizes of 400 to 1600 #m 2, were used. The nylon bags were hung for 48 h in the rumen of fistulated cattle maintained on barseem hay. The calculated amount of sample (10 mg/cm 2 of bag surface area) was weighed in the nylon bag. The material incubated was allowed to move freely within the bags so as to avoid the formation of microenvironments in the bags.

RESULTS AND DISCUSSION

The data related to the digestibilities are shown in Table 1. Among the cereal and pulse by-products studied so far, maize gluten meal was found to have 64.11 ~o dry-matter digestibility compared with the nitrogen degradability value of 60~o for maize reported by Mehrez & Orskov (1977). In the case of rice husk the observed value of digestibility (23-23 ~) was in the range of dry-matter digestibility in vivo figures reported by Chandra & Johri (1953).

The Agricultural Research Council (1980) recommendations suggest that if the assumed value for degradability is too low the rumen microbes will receive more degradable nitrogen than they need and the amount of dietary protein reaching the small intestine will be underestimated. An overestimation of degradability may result in short supply of nutrients required for microbial growth in the rumen. Thus the present nylon-bag dry-matter digestibility values could be of help in a preliminary screening in judging whether a particular agroindustrial byproduct or waste could be utilised or not in the practical diet of ruminants as suggested by Orskov et al. (1980).

REFERENCES

Agricultural Research Council (1980). The nutrient requirements of ruminant livestock. Commonwealth Agricultural Bureau, England.

Chandra, K. & Johri, P. N. (1953). Rice husk as cattle feed. Proc. Indian Sci. Congr., 40, 252 (Abstr.).

Mehrez, A. Z. & Orskov, E. R. (1977). A study of the artificial fibre bag technique for determining the digestibility of feeds in the rumen. J. Agric. Sci., 88, 645-50.

158 Gopal Kr&hna

Orskov, E. R., Hovell, D. D. & Mould, F. (1980). The use of the nylon bag technique for the evaluation of the feedstuffs. Tropical Animal Production, 5, 195-213.

Gopal Krishna,* Department of Animal Nutrition, Haryana Agricultural Uni~,ersity, Hissar (125004), Haryana, lndia

* Present address: Weende Experiment Station, Institut fiir Tierphysiologie und Tierern~ihrung, Der Universit/it G6ttingen, Oscar Kellner Weg. 6, 3400-G6ttingen- Weende, West Germany.