Effects of replacing concentrates with Atella (a byproduct of local beer) on growth performance of Hararghe Highland sheep in Ethiopia

Ayfokir Tadesse, Mengistu Urge¹ and Meseret Girma¹

Department of Animal Sciences, Mizan -Tepi University, PO Box 21, Mizan Tepi, Ethiopia
¹ School of Animal and Range Sciences, Haramaya University, PO Box 138, Dire Dawa, Ethiopia
meseretgirma4@gmail.com

Abstract

Tella is a traditional home-brewed local beer in Ethiopia, and Atella is its residue. The focus of this study was to evaluate the use of Atella replacing concentrates for Hararghe highland sheep fed a basal diet of pasture grass hay. The treatments were 4 levels of Atella (0, 33, 66 and 100%) replacing a concentrate mixture of wheat bran, maize and noug seed cake (2:1:1) fed at 350g/d to yearling Hararghe highland male sheep as a supplement to natural pasture hay offered ad libitum. The experimental design was a random block of 4 treatments with 6 replicates. Twenty-four sheep with an initial body weight of 16.0±2.5 kg were housed in individual pens and fed the diets for 90 days.

DM intake of the sheep fed ad libitum was not affected by replacing all the concentrate by the beer byproduct “Atella”. There were major improvements in live weight gain and feed conversion as the Atella replaced 33% of the concentrate component (13% of the total diet) followed by a marked deterioration in these criteria as the Atella was further increased to replace all the concentrate (41% of the total diet). The poorer growth rate and feed conversion as the Atella exceeded 13% in the diet were not explained by feed intake nor by the digestibility of DM or crude protein, which were either unchanged (DM) or improved (crude protein) by the increasing level of the beer byproduct in the diet.

Keywords: beer, brewers' grains, byproduct, non-conventional feed, tata, tella, yeast

Introduction

The heterogeneity of culture in Ethiopia has resulted in the production of a diverse range of indigenous fermented beverages across the country (Binitu 2016). Tella is a traditional home-brewed local beer and Atella is its residue. It is produced in large amounts all year-round. A small proportion of this by-product is used in feeding dairy cattle, but large quantities accumulate at production sites causing disposal and public health problems (Demeke 2007). The focus of this study was therefore to evaluate the use of Attela replacing concentrates for Hararghe highland sheep fed a basal diet of pasture grass hay.

Materials and methods

Preparation of Atella

To prepare Tella (Bikila 2020; Mooha et al 2015), the requirements are: 1 kg of leaves of the Gesho tree (local “hops”) (Rhamnus prinoides), 0.5 kg of malt, 5 kg of unleavened bread, 10 kg of flour (maize and/or barley) and 30 liters of water.

Malt (germinated wheat) is prepared by placing moist grains between fresh Gesho leaves, left to germinate for 3 days and then dried. Ground Gesho leaves are placed in a clay container with water and left to ferment for 2-3 days. Sorghum flour is made into dough and baked to make unleavened bread which is mixed with the malt and pounded Gesho stems and added to the fermented ground gesho leaves in the clay container, and allowed to ferment for 1-2 days. Mixed maize and barley flour (1:1) is sprinkled with water and toasted until dark brown. This mixture plus the malt is added to the container. The container is kept sealed to create an anaerobic condition and left for 2 days, after which more water is added the container which is kept sealed for 5-7 days, when the beverage is ready. Tella can be kept for 10-12 days. Tella-Atella is the by-product (residue) of Tella production). In the process of tella fermentation there is no deliberate yeast introduction as starter culture. The yeast cells involved in the fermentation process come from the Bikil (malt) and Gesho (local hops) (Haimanot, 2011). The final alcohol content of Tella is 2-4%. Tella-Atella (or Atella) is the by-product (residue) of Tella production.

Location

The feeding trial was conducted at Haramaya University goat farm from 3 February to 18 June 2019.

Treatments and design

The treatments were four levels of Atella (0, 33, 66 and 100%) replacing a concentrate mixture of wheat bran, maize and noug seed cake (2:1:1) fed at 350g/d to yearling Hararghe highland male sheep as a supplement to natural pasture hay offered ad libitum. The experimental design was a random block of 4 treatments with 6 replicates. Twenty-four sheep with an initial body weight of 16.0±2.5 kg were housed in individual pens and fed the diets for 90 days following an acclimation period of 14 days. The animals had previously been vaccinated against pasteurellosis and sprayed against the common parasites.

Feeds and management

The Atella was collected consecutively for forty-five days from local Tella producer households in Hamaresa, Gendey-boy and Adele, East Harerghe, Ethiopia. It was immediately sun-dried and stored in sacks under shade. Noug seed cake, maize grain and wheat bran were purchased locally. These feeds were mixed in the ratio of 1:1:2 and ground through a hammer mill to 1-2mm size.

The supplement (350 g/d) was offered at 0800 and 1600 hours. The natural grass hay and water were offered ad libitum

Growth performance and feed conversion

The initial body weight of the sheep was taken at the end of the quarantine period and at ten day intervals throughout the feeding trial.

Digestibility trial

At the end of the feeding trial, the sheep were harnessed with bags to collect feces which were stored frozen daily over a period of 7 days. At the end of the trial, the fecal samples from each animal were mixed, thawed to room temperature and a sub-sample of about 10% dried at 60^oC for 72h.

Chemical analysis

Samples of feeds offered, refusals and feces were ground to pass a 1 mm sieve mesh and analyzed for DM, ash and nitrogen, according to the procedures of AOAC (1990). Neutral detergent fiber (NDF) and acid detergent fiber (ADF) were analyzed by the methods of Van Soest and Robertson (1985)

Statistical Analysis

The data were subjected to analysis of variance (ANOVA) in a randomized complete block design using the general linear model procedure of SAS 9.1 software (SAS 2008). The model was Yij=µ + Ti +Bj+Eijk

Where; Yij = the response variable; µ= overall mean; Ti = treatment effect; Bj = block effect and Eijk = random error.

Results

The crude protein content of the Atella was similar to the generally reported value of 23% for industrial brewers’ grains according to Feedipedia.org. A similar product (Tata) from another region of Ethiopia was reported to contain -20.5% CP in DM (Gelgelo et al 2017). Similar protein values for Atella of 21.8 and 20.0% were reported by Solomon (2007) and Zewdie et al (2011).

Live weight and feed conversion

DM intake and the average crude protein content of the diets were not affected by replacing concentrates with Attela (Table 2). However, the responses in live weight gain and feed conversion were curvilinear with improvements in both criteria as Atella replaced 33% of the concentrate followed by increasingly poorer performance when the proportion of Atella exceeded 33% of the supplement (Figures 1 and 2).

Figure 1. Effect of Atella on liveweight gain of Hararghe highland sheep	Figure 2. Effect of Atella on feed conversion by Hararghe highland sheep

It is relevant to compare responses in growth of sheep to supplementation with “Tata” a similar byproduct to “Atella” (Gelgelo et al 2017). The dose response curves for liveweight gain (Figure 3) and feed conversion (Figure 4) were similar to what we observed for Atella.

Discussion

The curvilinear response in growth rate and feed conversion to increasing levels of Atella replacing concentrates is not explained by the feed intake which showed no change up to 67% concentrate replacement with Atella, and then only a minor reduction at the 100% level (Figure 3); nor by digestibility which did not vary over all levels of replacement (Table 3). In fact, crude protein digestibility showed a tendency ( R² 0.95) to increase with increasing levels of Atella in the diet (Figure 4).

Figure 3. Effect of Atella on feed intake of Hararghe highland sheep	Figure 4. Effect of Atella on apparent protein digestibility by Hararghe highland sheep

It is relevant to compare responses in growth of sheep to supplementation with “Tata” a similar byproduct to “Atella” (Gelgelo et al 2017). The dose response curves for liveweight gain (Figure 5) and feed conversion (Figure 6) were similar to what we observed for Atella.

Figure 5. Effect of “Tata” on liveweight gain of Black head Somali sheep sheep (Gelgelo 2017)	Figure 6. Effect of “Tata” on feed conversion by Black head Somali sheep sheep (Gelgelo 2017)

Related research on use of brewery by products as supplements to cassava foliage in diets for goats has been reported from Vietnam (Thuy Hang et al 2018). Similar dose response curves to increasing proportions of the byproduct were observed (Figures 7 and 8) although the point of inflection (ie: when growth began to decrease) was lower in the case of the beer byproduct fed to goats (4% of the diet) compared with the optimum level of Atella in the present study which was about 13% of the diet DM.

Figure 7. Growth response curve of goats to increasing percentage of brewers’ grain in a diet of cassava foliage (Thuy Hang et al 2018)	Figure 8. Feed conversion response curve of goats to increasing percentage of brewers’ grain in a diet of cassava foliage (Thuy Hang et al 2018)

There is no obvious explanation of the curvilinear growth and feed conversion responses of sheep and goats to increasing levels of brewery byproducts in their diet. Our data show it is not explained by feed intake nor by digestibility which were not affected by the level of addition of the brewery byproduct.

Conclusions

• DM intake of sheep fed ad libitum native grass hay and 350 g/d of a concentrate (2:1:1 ratio of wheat bran, noug cake and maize grain) was not affected by replacing all the concentrate by the beer byproduct “ Atella”
  
  
• There were major improvements in live weight gain and feed conversion when Atella replaced 33% of the concentrate component (13% of the total diet) followed by a marked deterioration in these criteria as the Atella was further increased to replace all the concentrate (41% of the total diet).
  
  
• The poorer growth rate and feed conversion as the Atella exceeded 13% in the diet was not explained by feed intake, nor by the digestibility of DM or crude protein, which were either unchanged (DM) or improved (crude protein) by the increasing level of the beer byproduct in the diet.

References

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Received 5 May 2020; Accepted 21 May 2020; Published 1 July 2020

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