Received Date: May 24, 2016; Accepted Date: June 25, 2016; Published Date: July 10, 2016
Citation: Mengistu U, Kefelegn K, Gebretnsae WM (2016) Effects of Supplementing Cactus Cladode and Acacia Senegal Branches on Intake, Digestibility and Body Weight Gain of Tigray Highland Sheep Fed Barley Straw. J Fisheries Livest Prod 4:191. doi: 10.4172/2332-2608.1000191
Copyright: © 2016 Mengistu U, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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The primary objective of the experiment was to evaluate the effect of supplementing different proportions of dried cactus cladode (CC) and Acacia senegal branches (ASB) fed barley straw (BS) on feed intake, digestibility, and average daily gain (ADG) using twenty four yearling male Tigray highland sheep. Experimental sheep were blocked in to six blocks of four animals based on initial body weight and randomly assigned to one of the four treatments. Treatments were ad libitum feeding of BS+60 g noug seed cake (T1, control), and T2, T3 and T4 were supplemented with 240 g CC+80 g ASB, 160 g CC+160 g ASB, and 80 g CC+240 g ASB DM/day, respectively in addition to T1 ration. The experiment was consisted for 90 days of feeding trial and 7 days of digestibility trials. The inclusion of ASB was significantly increased CP content of cactus cladode by 28.2, 45.1 and 54.5% for T2, T3 and T4, respectively. Neutral detergent fiber (67.6%), acid detergent fiber (57.6%) and acid detergent lignin (18%) of acacia senegal branches also decreased by 20.2, 13.7 and 11.4%; 25.4, 16.8 and 11.1%; 10.7, 5.0 and 3.6%, respectively in those treatment through the inclusion of cactus cladode. the CP intake, ADG and Feed conversion efficiency were significantly increased (P<0.05) with increasing proportion of ASB in the foliage mixture. It can be concluded that supplementation with high proportion of ASB in the mixtures has a tendency to improve growth performance of sheep.
Cactus; Acacia; Intake; Digestibility; Weight gain; Sheep
CC: Cactus Cladodes; ASB: Acacia Senegal Branches; BS: Barley Straw; ADG: Average Daily Gain; DM: Dry Matter; CP: Crude Protein; OM: Organic Matter; NDF: Neutral Detergent Fiber; ADF: Acid Detergent Fiber; T1: Treatment One; T2: Treatment Two; T3: Treatment Three; T4: Treatment Four; SEM: Standard Error of Mean
Ethiopia has a diverse indigenous sheep population and their demand as live animal or as meat form is increasing from time to time by domestic and foreign markets [1,2]. This increased demand creates an opportunity to substantially improve food security of the population and alleviate poverty . However, sheep in Ethiopia consume feeds that contain a lot of fiber during most part of the year. And reliance on crop residues is ever increasing as more land is cropped . The bulky and fibrous nature of these feeds resulted in poor nutrient supply and reduced productivity of sheep.
To keep consistency of sheep productivity, recognizing appropriate indigenous feed resources like acacia and cactus is the best option. Hence, indigenous multipurpose trees have great potential to endeavour feed availability, chemical constituents and digestibility of feeds [5,6]. They have significant role in ruminant nutrition, because of their resistance to heat, drought, grazing and repeated cutting .
Cactus (Opuntia ficus-indica) is available in almost every farmer’s backyard of eastern and southern parts of Tigray regional states of Ethiopia [8,9]. Fresh cactus has high water content (90%) and can serve as water sources during dry season for animals . However, the extremely high water content may affect total dry matter intake, especially where water is not a limiting factor for animal production . The intake of total digestible nutrient can be increased if the fresh cactus is wilted or dried before feeding .
Cactus cladode has high capacity to store nutrients, even in extremely hot environment . It is rich in soluble carbohydrates and calcium, but poor in protein [10,14]. Thus, supplementing with appropriate and easily available protein sources like Acacia is mandatory.
Browse leaves from Acacias could form good sources of crude protein and mineral supplements to ruminants [15,16]. Acacia senegal is one of the major multipurpose trees that widely abundant in most parts of Ethiopia . Leaves of Acacia senegal has good nutritive value and may be suitable as supplementation of roughage feeds, but the collection of sufficient quantity is difficult, because of the thorns and small size of leaves [18,19]. Although, indigenous multi-purpose trees are not yet scientifically used throughout the country, the foliage mixtures of cactus cladodes and Acacia senegal branches may complement each other and serve as a good supplement to poor quality feeds and can support animal growth. Thus, the study was conducted, to evaluate the effects of supplementing dried cactus cladodes and edible branches of Acacia senegal on feed intake, digestibility and body weight gain of Tigray highland sheep .
The experiment was conducted at Ganta-Afeshum Woreda, which is located at 14? 16' N latitude and 39? 27' E longitudes with an elevation of 2457 meter above sea level. It has Weina-Dega climate, with 552 mm mean annual rain fall and 16°C temperature (BoANRD, 2009 unpablished docment).
The experiment was carried out in a randomized complete block design with six male Tigray highland sheep per treatment. Treatment diets were consisted: barley straw (BS)+60 g noug seed cake (NSC), BS+60 g NSC+240 g cactus cladode (CC)+80 g Acacia senegal branches (ASB), BS+60 g NSC+160 g CC+160 g ASB, BS+60 g NSC+80 g CC+240 g ASB for T1, T2, T3 and T4, respectively. Cactus cladode was collected and prepared by removing the spine with fire, then both CC and ASB were chopped approximately 1-2 cm length and dried by sun for two and one days, respectively and stored separately in sacks. The dried CC and ASB were mixed according to their ratio at each feeding and offered to experimental sheep on DM base at 08:00 and 16:00 h. The basal diet, barley straw was offered ad libitum at 25% refusal adjustment and 60 g noug seed cake was offered to all experimental sheep at 08:00 h to keep their maintenance level. Feed consumption and refusals were recorded daily to determine feed intake and sub-sampled for chemical analysis. Feed intakes were determined as the difference between the quantity of feed offered and refused for each sheep.
Body weights (BW) of experimental sheep were measured at ten days interval throughout the experiment to determine BW change. The average daily gains (ADG) were calculated as the difference between final and initial BW divided by number of feeding days. The feed conversion efficiency was determined by dividing the ADG to the amount of daily feed consumed while feed conversion ratio was determined by dividing the average daily feed intake to ADG. At the end of the feeding trial, all experimental sheep were transferred to digestibility trial and fitted with fecal collection bags to which they acclimatized for three days followed by seven days of total feces collection. The apparent digestibility coefficients (DC) of DM, OM, CP, NDF and ADF of feed samples were calculated by using the equation of :
Samples of experimental feeds, refusals and feces were ground to pass through 1 mm sieve at Haramaya University Nutrition Laboratory. The DM, Ash and CP contents of feeds, refusals and feces were determined according to  procedure. Organic matter was computed by subtracting the Ash content from 100. The NDF, ADF and ADL were analyzed by using the procedures of .
Data were analyzed using the analysis of variance model for completely randomized block design by employing the general linear model procedure . Differences among treatment means was tested using least significant difference (LSD) test. The statistical models used for analysis of the data collected were:
Where: Yij=response variable (the observation in jth block and ith treatment).
Chemical Composition of Treatment Feeds The inclusion of acacia senegal branches was significantly increased the crud protein (CP) content of cactus cladode by 28.2, 45.1 and 54.5% for T2, T3 and T4, respectively (Table 1). Not only was that, the neutral detergent fiber (67.6%), acid detergent fiber (57.6%) and acid detergent lignin (18%) of acacia senegal branches also decreased by 20.2, 13.7 and 11.4%; 25.4, 16.8 and 11.1%; 10.7, 5.0 and 3.6%, respectively in those treatment through the inclusion of cactus cladode.
|Feed offered||Chemical composition|
|(% DM)||(% DM)||(% DM)||(% DM)||(% DM)|
|Barley straw (T1)||92.6||3.2||88.5||63.9||7.9||8.1|
|Barley straw (T2)||92.9||3.3||87.1||63.8||7.2||7.1|
|Barley straw (T3)||92.8||3.3||86.4||62.7||7.2||7|
|Barley straw (T4)||92.5||3.5||85.3||62.9||7.1||9.1|
|DM: Dry Matter; CP: Crude Protein; NDF: Neutral Detergent Fiber; ADF: Acid Detergent Fiber; ADL: Acid Detergent Lignin; NSC: Noug Seed Cake; CC: Cactus Cladodes; ASB: Acacia Senegal Branches.|
Table 1: Nutritive value of experimental feeds and Refusals.
Dry matter and nutrient intake and their digestibility
The intake of dry matter (DM), organic matter (OM), crud protein (CP), nutrient detergent fiber (NDF), and acid detergent fiber (ADF) were significantly influenced by the addition of foliage mixtures (Table 2). Moreover, the intake of crud protein and acid detergent fiber were significantly increased (P<0.05) as the proportion of acacia senegal branches increased in the foliage mixture.
|Barley straw DM||404.7a||355.3b||351.8b||349.8b||5.72|
|Average DM (%BW)||2.8b||3.9a||3.7a||3.6a||0.13|
|Total DM (g/kgw.75)||56b||80.7a||78.8a||76.3a||2.37|
|a-cMeans within a row not bearing a common superscript are significantly different; OM: Organic Matter; SEM: Standard Error of Mean.|
Table 2: Daily dry matter and nutrient intake of experimental sheep during feeding trial.
Apparent digestibility of DM, OM, CP, NDF and ADF were significantly higher (P<0.05) in the supplemented groups than none supplemented but there were no significant differences (P > 0.05) among supplemented treatments (Table 3). Thus, the result indicated that foliage mixtures have higher tendency of digestibility than barley straw and their interaction is important to compensate each other. Digestibility of feeds influenced not only by its own composition, but also by the composition of other feeds consumed with it . Digestibility of low quality feeds can be increased through the action of rumen microbes by strategically mixing nitrogen and minerals that are deficient in these feed resources . The increase in digestibility of crop residues in turn also increases their intake then enhances the efficiency of nutrient utilization from these feed resources.
|Digestibility coefficient (%)||Treatments|
|a-bMeans within a row not bearing a common superscript are significantly different;
DM: Dry Matter; OM: Organic Matter; CP: Crud Protein; NDF: Neutral Detergent Fiber;
ADF: Acid Detergent Fiber; SEM: Standard Error of Mean.
Table 3: Apparent dry matter and nutrient digestibility of Tigray highland sheep.
Body weight change and feed conversion efficiency of Tigray highland sheep
The final body weight (FBW), average daily gain (ADG) and Feed conversion efficiency (FCE) were significantly increased (P<0.05) with increasing proportion of Acacia senegal branches (ASB) in the foliage mixture (Table 4). However, FCR was significantly increased (P<0.05) as proportion of cactus cladode increased in the foliage mixture.
|FCE (g ADG/g DMI)||0.004d||0.03c||0.041b||0.053a||0.01|
|FCR (g DMI/g ADG)||17.5c||31a||24.3b||19.1c||1.18|
|a-dMeans within a row not bearing a similar superscript letter significantly differ;
IBW: Initial Body Weight; FBW: Final Body Weight; BWC: Body Weight Change;
ADG: Average Daily Gain; FCE: Feed Conversion Efficiency; FCR: Feed
Conversion Ratio; SEM: Standard Error of Mean.
Table 4: Body weight and feed conversion efficiency of experimental sheep.
In the current finding, the nutritive value of acacia senegal branches was recorded lower than the values from leaves and from leaves and pods of acacia senegal [18,19]. The reason may be due to the inclusion of all parts of the branches (twigs, bark, leaves and stick) in the current study for simulating practices of farmer’s efficient uses of resources and to save time spent for leave collection. In accordance with the result obtained in the present study, Norton  suggested that fraction of tree foliage contain higher stem and to be of lower nutritive value than leaves alone. Sanon et al.  and Ondiek  also noted that Browse and collection of leaves from Acacia senegal were difficult, since younger individuals have smaller leaves and dense thorns. Hence, the present method of preparation could avoid this problem.
Regarding intake, the increased intake of crude protein associated with the proportion of acacia senegal may be due to leguminous nature of the tree. Because of the ability of Acacia to fix nitrogen, they have adequate crude protein contents for animal production  and high carbohydrate quality of cactus can be used as part of a complete diet with diet contains an adequate amount of degradable protein . Thus, the complementarities of those foliage mixtures were confirmed as expected to give some nutrient that can enhance sheep productivity. According to Diego and Gimenez  and Holst and White , the protein content of the whole diet needs to be above 15% protein for maximum growth rate, protein levels as low as 11% will enable some growth and feeds 8-9% crude protein may meet maintenance requirements of sheep. Thus, the results indicated that supplementing poor roughage with foliages of relatively better nutrient content increase total intake and acacia senegal branches have a potential to improve crud protein intake of sheep consumed low quality feeds at low cost.
The average daily gain result indicated that higher consumption of cactus cladode is needed for weight gain of sheep than acacia senegal branches due to its lower crud protein content. If a diet is low in protein or deficient in essential amino acids, feed intake of animals increase until their nutrient requirements are satisfied . Thus, the foliage mixtures of cactus cladode and acacia senegal branches have the potential to improve growth and productivity rate of sheep in arid and semi-arid areas, especially in the dry season through complementarities of interaction.
Considering the results of this study, supplementing foliage mixtures of cactus cladode and Acacia senegal branches have a positive effect on feed intake, feed conversion efficiency and average daily gain. The effects are more pronounced at higher proportion of Acacia senegal branches supplementation. Therefore, it is concluded that supplementation of 240 g dry mater Acacia senegal branches and 80 g cactus cladode to barley straw based diet can be used for improved sheep productivity at smallholder level, especially in the dry season.
We want to thank all technicians of animal nutrition and soil chemistry laboratories of Haramaya University, for their valuable comments and cooperation in laboratory analysis of the experimental feeds and feces samples. Funding for this study was provided by Ethiopian Ministry of Education, Ethiopia.