Evaluation and improvement of the nutritive value of sugar cane tops fed as sole diet to goats or supplemented with groundnut cake or sorghum grain

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1 29 Evaluation and improvement of the nutritive value of sugar cane tops fed as sole diet to goats or supplemented with groundnut cake or sorghum grain Ali, H.A.M. 1*, Abubakr, O. I. 2 and Sulieman, Y.R. 2 1 Graduate College, University of Bahri* Corresponding Author. hafizabdo@hotmail.com. Khartoum- Sudan 2 College of Animal Production, University of Bahri, Khartoum-Sudan Date Received, May 18, 2015 Date Accepted, June 22, 2015 Abstract: Sugar cane tops (by-products of cane sugar industry) are important feed resource in many sugar cane producing countries and Sudan is one of the biggest African sugar producers. The present study was undertaken to assess the nutritive value of sugar cane tops (SCT) as feed for goats. Sugar cane tops were treated with 5% urea solution prior to the start of the feeding trial. Nine males of Nilotic goats were used in a trial of 39 days duration. The goats were grouped randomly into three groups (three animals each) and assigned to one of the experimental rations following a completely randomized design. The rations were: (1) Urea-treated sugar cane tops (TCT) (Control), and ( 2) TCT supplemented with 100 g/ day groundnut cake or (3) TCT supplemented with 100 g/day sorghum grain The results showed that urea treatment increased CP concentration from 2.76% in untreated sugar cane tops (UTC) to 11.83% in TCT. Dry matter intake (DMI) of SCT was not affected when supplemented with either groundnut cake or sorghum grain. However, supplementation had significantly (P<0.05) increased total dry matter intake (DMI) and the nutrient digestibility. Rumen degradation and the degradation characteristics of dry matter were improved by urea treatment. It was concluded that the nutritive value of sugar cane tops could be improved by urea treatment and supplementation with protein and energy sources as reflected in increased CP level, dry matter intake, digestibility and degradation characteristics and is recommended to be included in the rations for goats. Keywords: Sugar cane tops, urea treatment, digestibility, intake, Fenugreek seeds, Nilotic goat. I.INTRODUCTION Sudan ranks top of Arab countries in relation to animal wealth and is second to Ethiopia in African countries. The national herd were estimated to be around 140 million heads of cattle, sheep, goats and camels [1]. Goats are spread all over the country and are mostly owned by people of low-socioeconomic status. Yet, a large percentage of livestock population suffers from acute shortage in animal feeds which is mainly attributed to deterioration of rangelands, shrinkage of areas allocated for irrigated fodders and high prices of concentrates. It is well documented that for most animal production systems, feed and feeding constitutes 50% to 80% of the total cost of production, hence, any reduction in the cost of feeding could improve the economical efficiency of production [2].Crop residues or by-products could be an important, low cost feed resource for animals in developing countries. These residues are characterized by low energy and protein contents and low digestibility which limits their utilization as feeds for animals. Sugar cane tops are one of the main by-products of cane sugar industry representing 15 to 25% of the aerial part of sugar cane [3]. Sugarcane tops, and particularly the immature stalks, are highly palatable with good intake characteristics in

2 30 livestock [3]. However due to the low protein, minerals and energy contents, feeing SCT as sole diet for ruminants is limited [4, 5 & 6]. The low nitrogen content of sugar cane tops could be increased by adding urea or a urea-molasses mixture during ensiling process [7]. In Sudan, and as a result of expansion in cane sugar industry (more than 5 factories) sugarcane tops are available in great quantities that if properly utilized could constitute an important feed resource for animals particularly ruminants. The objectives of the present study was to evaluate the digestibility and degradability of urea treated sugar cane tops fed as sole diet to goats or supplemented with groundnut cake or sorghum grain. II. MATERIALS AND METHODS Location of the Study: The present study was carried out at University of Juba experimental farm at Elkadaro, Khartoum North, Khartoum, Sudan. Urea- treatment of sugar cane tops: Chopped sugar cane tops were treated with 5% urea solution in an air tight bag which was kept for three weeks. The bags were then empted in a plastic sheet and left to dry for one day prior to chemical analysis. Experimental Animals and Design: Nine males of Nilotic goats were used in a feeding trial of 39 days duration. The goats were divided into three groups (three animals each) and assigned to one of the experimental rations (treatments) following a completely randomized design. The experimental rations were (1) Ureatreated sugar cane tops (TCT) at a rate of 250 g/day (Control), (2) TCT (250 g/day) + Sorghum grain (SG) at a rate of 100 g/day (R1) and (3)TCT (250 g/day) + Groundnut cakes (GNC) at a rate of 100 g/day (R2). The animals were housed in individual pens. For the measurement of degradability, a rumenfistulated bull (3 years old, 250 Kg body weight) receiving a diet consisting of sorghum, wheat bran and ground nut hulls was used. A known amount of feed was offered once a day and the residue was recorded next morning to calculate the intake by difference. In vivo digestibility trial: The digestibility trial was done by total faecal collection for each individual animal in each group (3 X 3 Latin square designs) [8]. The goats were kept in metabolism crates for 17 days. Faeces were collected quantitatively during the last 7 days of each feeding period. A sub sample (10%) was stored for analysis and digestibility calculation. The goats had free access to experimental feeds. Any feed left-over's were measured daily. Dry matter digestibility was calculated as follows: Digestibility (%) = dry matter consumed-dry matter in faeces X 100 dry matter consumed Measurement of degradability in situ: The degradability of SCT was measured in a fistulated bull according to the nylon bag technique described by [9]. Nylon bags of 30 cm 3 weighing 6 grams each were used. The bags were washed, oven dried at 60 o C overnight then individually weighed and their weights were recorded. Two grams of oven dried sample was put in the bag, tied with a nylon ribbon and introduced into plastic tube of 6cm above the fistula level to ease the movement of the bags inside the rumen. The bags (6 bags/bull/period) were incubated for different periods of time 9, 12, 24, 36, 48 and 72 hr. Bags were immediately removed at the end of each period of time, thoroughly washed under tap water, oven dried, cooled in a desiccator and weighed. Dry residues in the bag were calculated. The percentage of dry matter loss was calculated as follows: Wt of incubated sample wt. of residue after incubation Wt. of incubated sample

3 31 The dry matter disappearance at zero time (soluble fraction) was estimated as the washing loss of samples weighed into the nylon bag and rinsed through running tap water. Residual samples after incubation were mixed, pooled and made ready for analysis. Where: p = t = a = b = c = The degradation kinetics of the incubated experimental rations may be described by curelinear regression of dry matter or crude protein loss from the bag with time [10]. p = a + b (1 exp-ct) Potential degradability Incubation time axis intercept at time zero represents soluble and complete degradable substrate that is rapidly washed out of the bag The difference between the intercept (a) and the asymptote, represents the insoluble but potentially degradable substrate which is degraded by the microorganism according to first-order kinetics. Rate constant of b function a, b and c are constant fitted by an interactive least squares procedure. Chemical Analysis: Feed samples were analyzed for CP and Ash according to [11]. Samples were also analyzed for Neutral Detergent Fiber (NDF) as described by [12]. Statistical Analysis: The obtained data from the study was analyzed (ANOVA) according to a completely randomized design using SAS [13]. The treatment means were compared by the Duncan s multiple range test. The results from the nylon bag experiment were analyzed using Fit Curve computer program [10]. Degradation characteristics were described by the equation P= a+b (1-e -ct ) [10]. III. RESULTS AND DESCUSSIONS Table 1 shows the effect of urea treatment on the chemical composition of sugar cane tops. Treatment of sugar cane tops with urea has increased CP, Ash and NDF contents. The crude protein content of sugar cane tops was increased from 2.76 % in UTC to % in the TCT. This increase in CP content as affected by urea treatment was observed by many workers [14, 15, 16, &17]. [18] studied the effect of urea spraying (3 %) on the chemical composition of 16 types of poor quality roughages and they reported an increase in CP of up to 14 %. In the results obtained by [19], the CP content of sugarcane top has increased from 1.25 to 6.75 % after urea treatment. Similarly, [20] found that treating of sugarcane top with 6% urea increased the CP content from 4.2 to 8 per cent. The low protein content of sugar cane tops limits their use as sole feed in ruminant diets [21] and hence it is suggested that urea treatment will increase the CP content of sugar cane tops to levels optimal for microbial degradation and hence will improve their utilization as feed for ruminants. The increase in the Ash content of urea-treated sugarcane tops observed in this study was also reported by [22]. The Ash content of UTC was lower than the results of 8.50% reported by [23]. With regard to cell wall constituents, the NDF content was increased by 2% after urea treatment (from 41% in UTC to 43% in TCT). This result contradicts the result obtained by [22] who observed a reduction of 6.78% in NDF content and [20] who observed a slight change

4 32 in fibre content with higher cellulose and lignin contents and lower hemicellulose content after urea treatment of sugar cane tops. The reduction in NDF content of sugar cane tops after urea treatment was also supported by [24]. treatment period, urea level, quality of forage material, temperature, hermetic condition and ureolysis reaction [22].. The variation in the nutrient content of untreated and urea treated sugarcane top reported in various studies might be due to differences in variety, harvesting stage, fertilization practices, Table-1. Effect of urea treatment on chemical composition (%) of sugar cane tops. Parameter UTC TCT CP ASH NDF UTC= Untreated Sugar Cane Tops, TCT= Urea-treated Sugar Cane Tops, CP= Crude Protein, NDF= Neutral Detergent Fiber. Dry matter intake of sugar cane tops, total dry matter intake of experimental rations and digestibility of experimental rations were presented in Table 2. There was no significant difference (P>0.05) in dry matter intake of sugar cane tops among experimental feeds. However it was observed that intake of sugar cane tops was decreased when offering animals supplements of sorghum grains and groundnut cakes. Intake of sugar cane tops was reduced from g in the unsupplemented tops to g and in the sorghum grain and groundnut cakes supplemented groups, respectively. On the other hand, Supplementing urea treated sugarcane tops with either, sorghum grain or groundnut cake had significantly (P<0.05) increased both total dry matter intake (TDMI) and digestibility (DMD) of experimental rations. TDMI values obtained were g, g and g for TCT, R1 and R2, respectively. Whereas those of DMD were 59.8 (%), 68.2 (%) and 76.8, respectively. Increase in dry matter intake of fibrous residues as affected by supplementation with protein and energy sources has been reported by [25], [26] & [27]. This increase indicated that supplementation has improved microbial fermentation. Sugarcane tops have been rarely fed alone to ruminants as animals might either lose condition or just maintain themselves or at best have very low levels of production [28]. With the low amount of digestible crude protein obtainable from SCT, it is logical that the first supplement should be a nitrogen source. [29] obtained average daily liveweight gains (ADG) of 0.52 kg by supplementing SCT with 1 kg cotton seed meal/hd/day while animals just maintained weight without the supplement. Table 2. Dry matter intake of sugar cane tops, total dry matter intake of experimental rations and dry matter digestibility of experimental rations. Parameter Treatment TCT (Control) R1 R2 Significance SE DMI (g) N.S TDMI (g) c b a * 4.24 DMD (%) 59.8 b 68.2 ab 76.8 a * 2.5 TCT= Urea Treated Sugar Cane Tops, R1= TCT (250 g/day) + Sorghum grain, R2= TCT (250 g/day) + Groundnut cakes, DMI= Dry Matter Intake of Sugar Cane Tops, TDMI, Total Dry Matter Intake, DMD= Digestibility of Experimental Feeds, a, b, c = Means in the same row bearing different superscripts were significantly different (P< 0.05). The degradability and the degradation parameters of untreated and urea treated sugarcane tops are presented in Table 3 and Table 4, respectively. Degradability values (%) measures at different incubation times were higher for TCT as compared to UTC. The degradability (%) of UTC was ranged from 19.5 for 0 h incubation to 41 for 72 h incubation, whereas that of TCT was ranged from 26 for 0 h incubation to 53 for 72 h incubation. Urea

5 33 treatment also increased the insoluble but potentially degradable fraction (b), soluble fraction (a), potential degradability (y) and effective degradability (P) (c). Urea treatment not only increased the potentially degradable fraction, but also its rate of degradation. Similar results were obtained by [30]. In Mauritius the degradation of SCT in nylon bags in the rumen of cattle fed a basal diet of poor quality fodder was found to be 43 percent after 48 hours. The degradability of the bundle leaf sheath was 50 percent higher than that of the green leaf blade after 48 hours of incubation in the rumen of cattle [31, Unpublished article]. Large variations exist in the literature for the nylon bag degradability of SCT. Some are real differences while part is due to the basal rations used. Table 3: Effect of urea treatment on the degradability (%) of sugarcane tops measured at different incubation times. Time (h) Degradability (%) UTC TCT UTC= Untreated Sugar Cane Tops, TCT= Urea-treated Sugar Cane Tops Table 4: Effect of urea treatment on the degradation parameters of sugarcane tops Parameter UTC TCT a b a+b c Potential degradability (y) Effective degradability (P) at: R= 0.03 R= 0.05 R= UTC= Untreated Sugar Cane Tops, TCT= Urea-treated Sugar Cane Tops, Y= a + b (1-e ct ), P= a +bc/c+r IV. CONCLUSIONS Sugar cane tops represent important feed resources for goats in Sudan due to their availability at low cost during the period when other green fodders are not available. The nutritive value of sugar cane tops was upgraded by treatment with urea as reflected by improvement in proximate nutrients, particularly CP, cell wall constituents (NDF) and

6 34 degradation characteristics. Also supplementation of sugar cane tops with groundnut cake and sorghum grain has improved the nutritive value of these resources as reflected by, total dry matter intake and dry matter digestibility. Supplementation with groundnut cake has resulted in higher intake and digestibility values as compared with sorghum grain. In Sudan, sorghum grain is used for human consumption and hence future research should concentrate on finding other forms of cheap ideal supplements and alternative techniques V. RECOMMENDATIONS VI. REFERENCES to improve the feeding value of sugar cane tops such as physical and biological means. [1] MOAR (2003). Ministry of Animal Resources, Annual Report. [2] Gillespie, James R. (1987). Animal Nutrition and Feeding. Delmar Publishers, Inc., Albany, New York. [3] Suttie, J. M., (2000). Hay and straw conservation for small-scale farming and pastoral conditions. FAO Plant Production and Protection Series No. 29, FAO, Rome. [4] Galina, M. A., Guerrero, M. and Puga, C. D. (2007). Fattening Pelibuey lambs with sugar cane tops and corn complemented with or without slow intake urea supplement. Small Ruminant Research, 70 (2-3): [5] Arcos-Garcia, J. L., Castrejon, F. A., Mendoza, G. D. and Perez-Gavilan, E. P. (2000). Effect of two commercial yeast cultures with Saccharomyces cerevisiae on ruminal fermentation and digestion in sheep fed sugar cane tops. Livestock Production Science, 63 (2): [6] Leng, R.A. and Preston, T.R. (1985). Constraints to the efficient utilization of sugarcane and its by-products as diets for production of large ruminants. In: R M Dixon (ed.), Ruminant feeding systems utilizing fibrous agricultural residues. International Development Program of the Australian Universities and Colleges, Canberra, Australia: [7] Alemzadeh, B. and Noroozy, S. (2006). Effect of different levels of sugarcane top silage in milk production of dairy cattle. Buffalo Bulletin, 25 (3): [8] Schneider, B.H. and Flatt, W.P. (1975). The evaluation of feeds through digestibility experiments. University of Georgia Press, Athens, Georgia, USA. 423 pp. [9] Mehrez, A.Z. and Orskov, E.R. (1977). A study of the artificial fibre technique for determining the digestibility of feeds in the rumen. Journal of Agricultural Science, 88: [10] Orskove, E.R. and McDonald, I. (1979). The estimation of protein degradability in the rumen from incubation measurements weighed according to rate of passage. Journal of Agricultural Science, Cambridge, 92: [11] (AOAC). Association of Official Analytical Chemists (1999). Official Methods of Analysis, 14th ed. AOAC, Washington DC, USA. [12] Van Soest, P. J. and Robertson, J. B. (1985). Analysis of forages and fibrous foods: A laboratory manual for animal science, 613. Cornell University, Ithaca, New, York, USA. 202 pp. [13] SAS Inc. (1996). SAS User s Guide: Statistics. Statistical Analysis Systems institute Inc., Cary, NC. USA. [14] Lawder, M. J. and O Shea, J. (1979). The effect of ammoniation on the intake and nutritive value of straw. Animal Feed Science and Technology, 4: [15] Shariff, M. A. and Gupta, B.N. (1987). Nutritive value of ammonia treated wheat straw. Indian Journal of Animal Science, 57:

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