Effect of replacing groundnut seedcake by brewers’ yeast-noug seed cake mixture in ration on laying performance of white leghorn chicken

Abstract

A study was conducted to evaluate effect of replacing groundnut seed cake with brewers’ yeast-noug seed cake (BYNSC) mixture on laying performance of white leghorn chickens. 180 white leghorn layers (28 weeks) were used in a completely randomized design. Five treatment rations in 3 replications with 12 hens were prepared. The treatments were replacing groundnut meal (T1 (0% BYNSC + 18% groundnut cake meal), T2 (4.5% BYNSC + 13.5% groundnut cake meal), T3 (9% BYNSC + 9% groundnut cake meal), T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal)). Daily dry matter intake was determined by subtracting ort collected from feed offered. Egg production was determined as hen-day (HDEP) and hen-housed egg production (HHEP). Crude protein (CP) and metabolizable energy of BYNSC were 38.74% and 3153.07 kcal ME/kg/DM, respectively. Hens fed T3 had significantly (P < 0.001) greater daily dry matter (DM) intake (95.4 ± 0.5 g) than T1 (91.3 ± 0.3 g), T2 (92.4 ± 0.8 g), T4 (89.2 ± 0.9 g) and T5 (88.6 ± 0.6 g). HDEP was significantly (P < 0.001) higher for layers fed T3 (65.5%) than T1 (58.2%), T4 (54.8%) and T5 (51.6%), while the value for T2 and T3 did not differ. Egg weight was statistically similar (P > 0.05) among the treatments. Hens fed T3 (2.3 ± 0.05) diet attained lowest (P < 0.05) feed conversion rate than T4 (2.7 ± 0.13) and T5 (2.8 ± 0.11) but similar with T1 (2.6 ± 0.03) and T2 (2.5 ± 0.04). Generally, replacing groundnut by BYNSC mixture up to 50% could increase egg productivity without any adverse effect.

Keywords:

• Groundnut
• brewers’ yeast
• poultry
• egg production
• layer

REVIEWING EDITOR:

• Pedro González-Redondo, University of Seville, Spain

SUBJECTS:

• Agriculture & Environmental Sciences; Zoology; Nutrition

1. Introduction

In the world where population number is increasing along with urban expansion, demand for livestock products in particular from poultry is expected to be twofold (Stino & Nassar, 2013). Chicken production in Ethiopia is the only supplier of egg and chicken meat for rural and urban area and is great source of income, especially to women. In spite of these Ethiopian chicken ecotypes are low in production potential of egg and meat, which required importation of improved exotic breeds (Sebho, 2016). Nonetheless, exotic chickens have high feed consumption behavior which is threat in an ever increasing of feed cost (Yemane et al., 2016). In Ethiopia feed availability in abundance and quality are varying across different seasons (Mekonnen et al., 2010).

Oil crops like groundnut in Oromia, Benshangul-Gumz and Amhara region, and noug seed are produced in different parts of Ethiopia (CSA, 2018). Groundnut and noug seed are used for edible oil production and the by-product groundnut and noug seed cake are used as livestock feed. However, the study showed that groundnut is scarce in specific amino acids necessary for poultry (lysine, methionine, tryptophan and threonine) (Ranjhan, 1993). Groundnut could be used as an alternative feedstuff for soybean meal, but it is susceptible to aflatoxins that lower egg production performance of hens (Alshelmani et al., 2021). Noug seed cake has been suggested as rich source of essential amino acid for poultry though it is low in tryptophan content and could complement with brewers’ dried yeast (Mekonnen et al., 2010).

According to Levic et al. (2010) the use of industrial by-products as animal feed could provide nutrients for poultry. Utilizing alternative feed ingredients like fermented feed sources in ration are vital for successful poultry production through performance improvement and lowering of feed cost (Alshelmani et al., 2021). Brewer’s dried grain and dried yeast are among the non-conventional feedstuffs used in poultry ration (Yalçın et al., 2014). Brewer’s by-products can be utilized as inclusion of brewer’s spent grains and yeast separately, as brewers’ yeast-grain mixture and combined with other feed sources (Zewdu & Berhan, 2014). Brewers’ dried yeast is better in critical amino acids compared to groundnut cake meal (Dana & Yami, 2005).

In Ethiopia about 26722.8 tons of brewers’ spent grains (DM) basis and 360,758.1 hectoliter (hl) of brewers’ spent yeast in the year 2016 were produced and dried form of spent brewer’s yeast has not yet extensively utilized in poultry feed (Kitaw et al., 2018). Exploitation of this industrial by-product may contribute towards better and economic feeding of poultry (Zewdu & Berhan, 2014).

Previous studies investigated that the nutritive value of brewer’s yeast could be used as good alternative source of animal feed (Chollom et al., 2017; Girma et al., 2012; Koiyama et al., 2018; Zewdu & Berhan, 2014). However, the real situations showed that brewer’s yeast has drying problem discouraging its use in dry form. Therefore, using this by-product feed mixed with feeds like noug seed cake with good CP to minimize the drying problem and maximize nutrient profile of rations is necessary. According to Bhagya and Sastry (2003) feeds with comparable nutrient content and blended each other possess synergy effect in poultry nutrition. Brewer’s yeast contains critical amino acids better than groundnut seed cake meal (Loong, 2013) and noug seed cake has amino acid profiles and CP needed for poultry (Bhagya & Sastry, 2003). Accordingly, brewer’s yeast-noug seed cake mixture (BYNSC) could be used as protein and amino acids source feed in poultry ration. Therefore, with the above background this study was designed to evaluate feed intake and egg laying performance of White leghorn chicken fed on BYNSC.

2. Materials and methods

2.1. Experimental farm

This experiment was conducted at Haramaya University (Ethiopia) poultry farm located at 42° 3΄ E longitude, 9° 26΄ N latitude and an altitude of 1980 m above sea level (Mishra et al., 2004).

2.2. Preparation of brewers’ yeast and noug seed cake mixture

Inactivated fresh brewers’ yeast was collected from Harar brewers’ company. Decantation of the liquid yeast was done two times to reduce the amount of water constituent present in the yeast. During decantation, the yeast was sediment underneath and the water constituent float on it. The floated water was then poured/removed/in to a container and discarded. Noug seed cake was ground before mixing. The ground noug seed cake and liquid brewers’ yeast were then mixed together. The proportion of brewers’ yeast-noug seed cake mixture was 70 liter of liquid brewers’ yeast (sediment) and 30 kg of noug seed cake according to Kamphayae et al. (2017) who used the liquid brewers’ yeast with cassava pulp. The mixture was mixed thoroughly in a bucket and then sun dried on clean plastic sheets.

Yeast from each day collection (after decantation) was stored in five-liter container, which was then sundried and weighed. The actual quantity of dried yeast mixed with noug seed cake was known in accordance with dried weight and amount of liter used. Accordingly, 16.2 kg dried yeast was mixed with 30 kg noug seedcake.

2.3. Management of experimental chickens

One week before the start of the actual experiment, the experimental pens, watering and feeding troughs as well as laying nests were thoroughly cleaned, disinfected, and sprayed against external parasites. 15 pens covered with straw litter material of 10 cm depth were prepared. Straw covered nests were placed for each individual pens. One hundred eighty (28 weeks old) white leghorn chickens were used after examined for outer anatomical defects and were randomly assigned into the 15 pens, consisting of 12 hens. The chickens were undergone acclimatization for one week and the experiment was conducted for 90 days in deep litter housing system.

Vitamin (1 g vit:2 liter water ratio) was given through drinking water for the first seven consecutive days. Chickens were provided feed by a cylindrical hanged tin and plastic made feeder, while, water was provided through round drinker at ad libitum base. Ort (leftover feed from the feed offered) from each pen was collected, weighed and recorded every morning at 7:00 hour.

2.4. Experimental design and treatments

The experiment was arranged in a completely randomized design and five dietary treatments each with three replications (Table 1). The treatment diets were T1 (0% BYNSC + 18% groundnut cake meal), T2 (4.5% BYNSC + 13.5% groundnut cake meal), T3 (9% BYNSC + 9% groundnut cake meal), T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal). After feed chemical analysis have done and based on the result obtained, five experimental diets with 16 to 17% CP and 2800 to 2900 metabolizable energy (ME) were formulated according to NRC (1994). The treatment rations were replacement of groundnut seed cake by brewer’s yeast-noug seed cake mixture. The maximum percent of groundnut seed cake in the control diet (T1) was 18% in which 100% groundnut was analogues to 18% level addition in the ration.

Table 1. Proportion of ingredients (%) used in the experimental rations.

Ingredients	Treatment
	T1	T2	T3	T4	T5
Maize	40	39	39.5	39	39.5
Wheat short	26.25	26.75	25.5	26.5	26
Groundnut cake	18	13.5	9	4.5	0
BYNSC (BY:NSC =35.07:64.93)	0	4.5 (1.58:2.92)	9 (3.2:5.8)	13.5 (4.7:8.8)	18 (6.3:11.7)
SBM	4	4.5	5	4.5	4.5
DCP	1	1	1.25	1.25	1.25
Limestone	8.5	8.5	8.5	8.5	8.5
Vitamin Premix	1.5	1.5	1.5	1.5	1.5
Salt	0.75	0.75	0.75	0.75	0.75
Total	100	100	100	100	100

SBM = soybean meal, BYNSC = brewers’ yeast-noug seed cake mixture, DCP = dicalcium phosphate, T1 (0% BYNSC + 18% groundnut cake meal), T2 (4.5% BYNSC + 13.5% groundnut cake meal), T3 (9% BYNSC + 9% groundnut cake meal), T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal), Vitamin premix 50 kg contains, Vit A = 2000000iu, Vit D3 = 400000 iu, Vit E = 10000 mg, Vit K3 = 300 mg, Vit B1 = 150 mg, Vit B2 = 1000 mg, Vit B3 = 2000 mg, Vit B6 = 500 mg, Vit B12 = 4 mg, Vitpp = 60000 mg, Folic acid = 160 mg, Choline chloride = 30000 mg, Anti-oxidant = 500 gm, Manganese = 10000 mg, Zinc = 14000 mg, Iron = 9000 mg, Copper = 1000 mg, Sodium = 200 mg, Calcium = 28.2%, Selenium = 80 mg.

2.5. Data collections

2.5.1. Feed chemical analysis

Representative samples of feed were taken from each of the feed ingredients used in the experiment for chemical composition analysis before formulating the dietary treatment. Samples from the compound diets and refusal were taken and kept in bags until analyzed. All samples were analyzed for DM, N, EE, CF and ash using the Weende or Proximate analysis methods of the (Helrich, 1990) at Haramaya University animal nutrition laboratory. Crude protein (CP) was determined by multiplying the N obtained by a factor of 6.25. Metabolizable energy (ME) of the experimental diets was determined using the equation described by Wiseman (1987): ME (kcal/kg DM) = 3951 + 54.4EE-88.7CF-40.8ash.

2.5.2. Dry matter intake

$$\begin{array}{c}\text{Mean \hspace{0.33em}daily\hspace{0.33em} DM\hspace{0.33em} intake}\hspace{0.17em}\left(g\right)\\ =\frac{\left(\text{feed\hspace{0.33em} intake}\hspace{0.17em}\left(g\right)\right)*\text{DM \hspace{0.33em}of \hspace{0.33em}offered}-\left(\text{ort}\hspace{0.17em}\left(g\right)*\text{DM \hspace{0.33em}of\hspace{0.33em} ort}\right)\hspace{0.17em}}{\text{duration \hspace{0.33em}of\hspace{0.33em} experiemnt}*\text{number \hspace{0.33em}of \hspace{0.33em}hens}}\end{array}$$

2.5.3. Egg production

Eggs were collected, recorded along with the number of birds alive on each day and summarized at the end of the experiment. Rate of lay for each treatment was expressed as the average percentage of hen-day and hen-housed egg production and computed for replication using Hunton (1995). $$\begin{array}{c}\text{\%Hen}-\text{day\hspace{0.33em} egg\hspace{0.33em} production}\\ =\frac{\text{Number\hspace{0.33em} of\hspace{0.33em} eggs\hspace{0.33em} collected\hspace{0.33em} per}\hspace{0.17em}\text{\hspace{0.33em}day}\hspace{0.17em}}{\text{Number \hspace{0.33em}of \hspace{0.33em}hens \hspace{0.33em}present \hspace{0.33em}that \hspace{0.33em}day}}*100\end{array}$$ $$\begin{array}{c}\text{\%Hen}-\text{housed\hspace{0.33em} egg\hspace{0.33em} production}\hspace{0.17em}\\ =\frac{\text{Sum of}\hspace{0.17em}\text{\hspace{0.33em}daily \hspace{0.33em}egg \hspace{0.33em}counts}\hspace{0.17em}}{\text{Number \hspace{0.33em}of\hspace{0.33em} hens}\hspace{0.17em}\text{\hspace{0.33em}orginally\hspace{0.33em} Housed}}*100\end{array}$$

2.5.4. Egg weight and egg mass

Eggs from each replication were weighed on a sensitive balance to the nearest 0.01 g accuracy and average egg weight was calculated by dividing the total egg weight to the total number of eggs (North, 1984). $$\mathrm{M}=\mathrm{P}\times \mathrm{W}$$ where M = average egg mass/hen/day; P = %hen – day egg production; W = average egg weight in gram.

2.5.5. Feed conversion ratio (FCR) and efficiency (FCE)

FCR and FCE were determined per replicate. $$\text{Feed \hspace{0.33em}conversion\hspace{0.33em} ratio}=\frac{\text{Mean\hspace{0.33em} daily\hspace{0.33em} feed\hspace{0.33em} intake}\hspace{0.17em}\left(g/h/\text{day}\right)}{\text{Egg \hspace{0.33em}mass}\hspace{0.17em}\left(g/h/\text{day}\right)\hspace{0.17em}}$$ $$\text{FCE}=\frac{\text{Dialy \hspace{0.33em}egg\hspace{0.33em} mass}\hspace{0.17em}\left(g\right)}{\text{Daily \hspace{0.33em}feed \hspace{0.33em}consumed}\hspace{0.17em}\left(g\right)}$$

2.6. Statistical analysis

The results were analyzed using the General Linear Model of Statistical Analysis System (SAS, 2002) and the difference between treatment means were separated using least significant difference (LSD) method (SAS, 2002).

The following model was used for data analysis. $${\mathrm{Y}}_{\text{ij}}=\mu +{\mathrm{T}}_{\mathrm{i}}+{\text{e}}_{\text{ij}}$$

• where Y_ij = is the j^th observation of the i^th treatment; µ = overall mean; T_i = is the i^th treatment effect (T1-T5) and e_ij = random error.

3. Results

3.1. Feed chemical composition

Feed ingredients (soybean meal, groundnut and BYNSC mixture) showed high crude protein content (Table 2). The CP and ME (kcal/kg) content of brewers’ yeast was 40.96% and 3564.7, respectively. The BYNSC mixture has CP content of 38.74%, which was lower than groundnut cake meal and better ME (kcal/kg) compared to groundnut cake meal.

Table 2. Chemical composition of feed ingredients used in the experimental ration.

Parameters	Maize	SBM	Groundnut	BYNSC	WS	BY	NSC
DM%	90.01	94.3	93.95	94.38	90.21	88.57	93.01
CP%	8.96	42.36	43.1	38.74	14.68	40.96	34.85
CF%	4.21	6.89	10.25	8.2	12.61	1.62	12.27
EE%	4.00	7.22	7.98	4.47	4.13	0.91	8.05
Ash%	3.54	6.31	8.51	7.69	4.52	7.16	9.21
Ca%	0.12	0.26	0.18	0.29	0.1	0.14	0.52
P%	0.26	0.56	0.72	0.91	0.65	1.35	0.67
ME(kcal/kg)	3620.74	3475.17	3128.72	3153.07	2872.74	3564.7	2924.8

DM = dry matter, CP = crude protein, CF = crude fiber, EE = ether extract, Ca = calcium, P = phosphorus, ME = metabolizable energy, SBM = soybean meal, BYNSC = brewers’ yeast-nougseed cake mixture, WS = wheat short, BY = brewers’ yeast, NSC = nougseed cake.

The crude protein content of the treatments was almost similar. However, CF content of the treatments was slightly decreased along with increasing level of BYNSC mixture (Table 3).

Table 3. Chemical composition of rations (DM basis).

Treatments
Chemical composition (%)	T1	T2	T3	T4	T5
DM	90.37	90.23	90.31	90.20	90.29
CP	16.58	16.64	16.84	16.49	16.28
CF	8.55	8.4	8.05	7.99	7.97
EE	3.3	3.28	3.31	3.2	3.0
Ash	11.94	12.27	13.2	12.75	12.43
Ca	3.43	3.44	3.57	3.52	3.48
P	0.58	0.54	0.55	0.5	0.46
ME (kcal/kg)	2884.98	2883.74	2877.93	2896.17	2900.01

DM = dry matter, CP = crude protein, CF = crude fiber, EE = ether extract, Ca = calcium, P = phosphorus, ME = metabolizable energy, T1 (0% BYNSC + 18% groundnut cake meal), T2 (4.5% BYNSC + 13.5% groundnut cake meal), T3 (9% BYNSC + 9% groundnut cake meal), T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal).

3.2. Feed intake

There was significant (P < 0.001) difference in feed intake among treatments (Table 4). Layers fed on T3 (9% BYNSC + 9% groundnut cake meal) recorded significantly (P < 0.001) high daily feed intake followed by T2 (4.5% BYNSC + 13.5% groundnut cake meal). The lowest DM intake was recorded by T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal).

Table 4. Performance of white leghorn chickens fed diet containing different levels of brewers’ yeast-noug seed cake mixture.

	Treatments
Parameter	T1	T2	T3	T4	T5	LS
DMI(g/h/d)	91.3b^c±0.3	92.4^b±0.8	95.4^a±0.5	89.2 ^cd±0.9	88.6^d±0.6	***
HDEP (%)	58.2^bc±0.8	60.9^ab±0.5	65.0^a±1.1	54.8 ^cd±2.5	51.6^d±0.7	***
HHEP (%)	56.7^bc±1.5	60.2^ab±0.2	63.1^a±1.2	54.6^c±2.6	49.4^d±0.7	***
EWt (g)	51.4 ± 0.45	51.38 ± 0.19	52.7 ± 0.55	50.8 ± 0.67	51.1 ± 1.23	NS
EM (g/h/d)	35.6^bc±0.41	37.3^b±0.31	40.8^a±1.07	33.1 ^cd±1.81	31.4^d ±1.18	**
FCR	2.6^bc±0.03	2.5^bc±0.04	2.3^c±0.05	2.7^ab±0.13	2.8^a±0.11	*
FCE	0.39^bc±0.004	0.40^ab±0.01	0.43^a±0.01	0.37^bc±0.02	0.35^c±0.01	**

^a,b,c,d row means with different superscripts are significantly different, ***= P < 0.001, **= P < 0.01, *= P < 0.05, T1 (0% BYNSC + 18% groundnut cake meal), T2 (4.5% BYNSC + 13.5% groundnut cake meal), T3 (9% BYNSC + 9% groundnut cake meal), T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal), DMI = dry matter intake, HDEP = hen day egg production, HHEP = hen housed egg production, EWt = egg weight, EM = egg mass, FCR = feed conversion ratio, FCE = feed conversion efficiency, LS = level of significance.

3.3. Egg production

There were significant (P < 0.001) difference in HDEP of chickens fed on the different levels of BYNSC mixture (Table 4) with T3 (9% BYNSC + 9% groundnut cake meal) recorded higher (P < 0.001) HDEP than T1 (0% BYNSC + 18% groundnut cake meal), T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal). Layers fed on T2 (4.5% BYNSC + 13.5% groundnut cake meal) recorded greater (P < 0.001) egg production performance than T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal) (Table 4).

3.4. Egg weight and egg mass

Egg weight was not influenced (P > 0.05) for hens fed the different levels of BYNSC (Table 4). However, there was an improvement (P < 0.01) in mean egg mass of chicken from T1 (0% BYNSC + 18% groundnut cake meal) to T3 (9% BYNSC + 9% groundnut cake meal), while, egg mass were significantly decreased in T4 (13.5% BYNSC + 4.5% groundnut cake meal) and T5 (18% BYNSC + 0% groundnut cake meal).

3.5. Feed conversion ratio and efficiency

The feed conversion rate (FCR) of chickens was significantly (P < 0.05) different among treatments and higher (P < 0.05) FCR of layers fed with T5 (18% BYNSC + 0% groundnut cake meal) as compared to T1 (0% BYNSC + 18% groundnut cake meal), T2 (4.5% BYNSC + 13.5% groundnut cake meal) and T3 (9% BYNSC + 9% groundnut cake meal) (Table 4). Layers fed with T3 (9% BYNSC + 9% groundnut cake meal) resulted in greater (P < 0.01) feed efficiency than the other treatments, except with T2 (4.5% BYNSC + 13.5% groundnut cake meal) which has recorded similar value. The lowest feed conversion efficiency was attained in T5 (18% BYNSC + 0% groundnut cake meal) followed by T4 (13.5% BYNSC + 4.5% groundnut cake meal).

4. Discussion

4.1. Proximate composition of feeds used in the experiment

The crude protein content of groundnut was comparable with the finding of Girma et al. (2012) (42.2%) and lower than the value (45.6%) reported by Batal et al. (2005). The difference in CP content of groundnut may be due to the variation in oil extraction process.

The high CP (40.96%) and ME (3564.7 kcal/kg) content of brewers’ yeast could make it as good sources of protein and energy for chickens. Aniebo (2011) indicated feeds like brewers’ yeast which are rich in protein content could improve the nutrient profile of feeds with less protein content.

The CP content of BYNSC mixture was lower than the report of Zewdu and Berhan (2014) for brewers’ dried yeast CP value (53.11%). However, it was higher than the CP content of 3.2, 6.8, 10.5, 14.1% for a ratio of liquid brewers’ yeast (%):cassava (%) pulp at 0:100, 10:90, 20:80, and 30:70, respectively (Kamphayae et al., 2017). This suggests blending comparatively better feeds in CP content like noug seed cake and brewers’ yeast could resulted in feed having better CP content. Amino acids profile of feed ingredients is critical issue in poultry ration. Therefore, BYNSC mixture could be used as protein, amino acids and energy source feed in poultry ration as brewers’ yeast contain critical amino acids better than groundnut seed cake meal (Loong, 2013).

4.2. Feed intake

The effect of inclusion of varying levels of BYNSC on feed intake of white leghorn layers ration on daily DM intake is shown in (Table 4). The higher (P < 0.001) feed intake of layers fed with T3 might be due to the formulation of the diet with required nutrients and amino acids. In addition, it might be due to synergy effect of noug seed cake and brewers’ yeast providing amino acids for layers (Bhagya & Sastry, 2003). Gbemiga Oladimeji et al. (2012) indicated that feeds with balanced proteins, amino acids and energy could increase feed intake and egg production of layers chicken.

The lower feed intake at the highest level of BYNSC mixture in ration might be due to slight remains of beer and hope and other unknown by-products in the yeast that could decrease feed intake of layers. In determining dry matter, protein, amino acids and other chemical compositions of autolyzed yeast (Saccharomyces cerevisiae), Podpora et al. (2015) used filtration process (to remove physical impurities) and centrifugation (to remove beer residue).

The result was in line with Blount (2016) who reported that feed consumption was significantly greater for hens fed yeast fermented product diet. In contrary, Hameed et al. (2019) reported absence of influence on feed intake of layers with yeast inclusion in layers ration. Moreover, Zewdu and Berhan (2014) reported that feed intake of white leghorn chickens fed on brewers’ grain-yeast mixture to 24:6 ratio was not influenced.

4.3. Egg production

The high performance of T3 and T2 in HDEP might be due to the high feed intake of layers and balanced nutrients (amino acids in BYNSC mixture). Swain et al. (2013) indicated that protein and better amino acid balance in poultry feed improve egg production performance. Similarly, Abdallah et al. (2016) noted synergistic effect of feed could improve the egg production performance of chickens. The low egg production performance, particularly in T5 and T4, may be due to low feed intake as the level of BYNSC increased in the ration. Similar to this finding, Girma et al. (2012) recorded significantly high egg production at 10% level of brewers’ dried yeast in replacing groundnut cake meal. Similarly, Ulmer-Franco et al. (2010) indicated improvement in egg production at 5% level of brewers’ dried grain inclusion in poultry ration. However, Özsoy et al. (2018) and Blount (2016) reported uniform egg production of laying hens fed on rations composed of Saccharomyces cerevisiae.

4.4. Egg weight and egg mass

The provision of metabolic energy and CP within the recommended range in all the treatment diets with the presence of minerals and vitamins could contribute to the uniform egg weight result obtained. Similarly, Koiyama et al. (2018) noted that yeast had no effect on egg weight of chickens. However, Swain et al. (2013) reported variation of egg weight of chickens fed with brewers’ dried grain at 5% level of inclusion.

The difference (P < 0.01) in mean egg mass could be due to differences in egg production of layers. This is because egg mass is a factor of egg weight and mean daily egg production. Desoky (2018) also obtained significant increment in egg mass of hens fed diets supplemented with dried yeast and vitamin C (Yeast + Vit-C). In contrary, Gebremedhn et al. (2019) reported uniform value of egg mass among different inclusion levels of brewers’ spent grain in bovans brown chicken ration.

4.5. Feed conversion ratio and efficiency

The low FCR in T3, T2 and T1 might be due to better combination of the feed ingredients and provided important nutrients required for layers. In addition, it may be due to the production of higher egg mass by the chickens, which could be related with feed quality. Balami et al. (2018) noted that a low feed conversion ratio is an indicator of high quality feeds.

The high FCE of T3 might be attributed to higher egg mass explained by feed quality increment at 9% inclusion level of BYNSC mixture. The lowest feed conversion efficiency gained by T5 followed by T4 might be due to the low feed intake at the highest level of BYNSC mixture inclusion. Ferket and Gernat (2006) indicated that feed intake could be a factor of feed efficiency in poultry. Similarly, Abdelrahman (2013) reported that the addition of yeast culture in ration improved feed conversion efficiency of layers. However, Girma et al. (2012) reported absence of difference in feed conversion efficiency of chickens fed on diets without or with inclusion of yeast.

5. Conclusions

Based on the results obtained it is concluded that, replacing groundnut seed cake by BYNSC up to 50% increased egg production performance of chicken without affecting the quality of eggs. Further research should be undertaken to simplify drying process of liquid spent brewers’ yeast. In addition, further study on the amino acid composition of spent brewers’ yeast mixed with important feed ingredients should be done.

Ethical consideration

This research fulfilled Farm Animal Welfare Council (2009) set principles to lessen suffering in terms of the five freedoms: 1) Freedom from hunger and thirst: access to fresh water and good nutrition. 2) Freedom from discomfort: suitable housing with protected areas to rest. 3) Freedom from pain, injuries, and diseases: prevention, diagnostics, and treatment. 4) Freedom to express normal behavior: sufficient space, adequate equipment, and contact with pen mates. 5) Freedom from fear and suffering: husbandry conditions and treatment that does not cause psychic suffering.

Acknowledgement

We are greatly gratified to thank Haramaya University and Ministry of Science and Higher Education in granting the research budget cost. In addition, we would like to thank Haramaya University poultry farm and its workers.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Notes on contributors

Endalamaw Yalew

Endalamaw Yalew is working as lecturer and researcher at Woldia University, Ethiopia.