Growth performance and Carcass Characteristics of broiler Chickens fed Graded levels of differently processed Rubber Seed Meal based Diets

— High cost of conventional feed ingredients has force many poultry farms to ford-up therefore call more researches in the use alternative feedstuffs which rubber seed meal is one. This experiment was therefore carried out to evaluate the growth performance and carcass characteristics of broiler chickens fed processed rubber seed meal (RSM) based diets in a six weeks straight feeding trial in completely randomized design with two by four factorial arrangement i.e. two processing methods (roasted rubber seed meal and` Hot water soaked sample and four equi-protein replacement of soybean meal levels (0, 15, 25 and 35% levels). The results revealed that the final weight (2150.00-2243.07g), weight gained (2106.00-2213.60g), daily weight gained (50.14-52.01g) average feed intake (101.89 -108.46), average feed consumed (4177.67- 4447.00g) and feed conversion ratio (1.91- 2.10) were not significantly (p ≥ 0.05 ) affected by dietary treatments. The dressed and eviscerated weights of broilers fed HRSM based treatment were significantly (p ≤ 0.05) higher than those that fed RRSM based treatment. Level interaction, treatment contrast and treatment and level interactions did not showed any significant (p ≥ 0.05) variation in all parameters measured suggesting rubber seed meal as suitable replacement of soybean meal in broilers chickens ration.


INTRODUCTION
Poultry products mostly meat, is a one meal size which did not require storage, it requires small space to rear, has short gestation period, can reach slaughter age within a short period. Thus, developing the poultry industry appears to be the fastest means of bridging the protein deficiency gap presently prevailing in Nigeria (Akinsanmi et al., 2017). Nigeria's feed production seem to be expanding rapidly in consistent with growth in the poultry industry. The business of raising poultry is cost-sensitive. Poultry feed accounts for higher percentage of the total feed produced in Nigeria (Agbede, 2019). The demand for poultry products has increased markedly over the past few years, due to the rapid growth specifically in the number of fast food restaurants featuring chicken menu in major urban areas (Akinnusotu et al., 2018). Profit of poultry farming mainly depends upon the economics of feeding the birds. Nigeria poultry industry is facing the problem of limited availability and high cost of conventional feed ingredients (Agbede, 2019). Therefore, search for alternative feedstuffs that can reduce cost of feed becomes a necessity. The use of unconventional feed sources like crop residues and agro-industrial by-products has been suggested to be the solutions to the problem of feed crisis in  (Olomu, 2011). The high energy and protein values of RSMs show that the meal could also be used as energy source and plant protein if it is properly processed (Oyewusi et al., 2007). though RSM is reported to be high in cyanide (18mg/100g) , those anti nutritional factors found in rubber seed are heat labile and are reduced to tolerable level while toasted (105 o C) or stored for 4-6 months before used . The seed meal or cake of rubber have been reported to have no any noticeable adverse effects on the health status of poultry birds (Akinsanmi et al., 2020) and contain higher contents of digestible nutrients than some conventional seed meals and are highly promising as future protein supplements in livestock and animal diets (Oyewusi et al., 2007).
Poultry birds can tolerate meal from undecorticated rubber seeds better than pigs because they have a gizzard to grind and help to digest the shell (Amaefule, et al., 2020). The crude protein content of rubber seeds and its products ranged between 22% in whole rubber seeds and 41% in commercial decorticated rubber seed meal (Eka et al., 2010).The utilization of rubber seed as a feed ingredient for monogastric animals has been limited by the presence of anti-nutritional factors especially hydrogen cyanide and the lack of proper processing methods that are cheaper and easy to adopt by the small scale rubber farmer or small scale poultry farmer living within the rubber producing zone of Nigeria (Akinsanmi et al., 2020) . This study was therefore carried out to assess growth performances and carcass characteristics of broiler chickens fed rubber seed meals based diets using two farmers' friendly processing methods and to establish the suitable incorporation levels of rubber seed meal in broilers feed.

Sample collection and study site
This experiment was carried out at the Teaching and Research Farm of the Federal University of Technology; Akure which is located between 7.15 o North and 5.0 o East of the equator with the average annual rainfall of 1524mm and annual temperature of 28 oc to 31 oc and mean annual relative humidity of about 80% (Ajibefun, 2011). The rubber seeds used for this study were purchased from Ilusin rubber estate, Ilusin, Ogun state, Nigeria.

Sample processing and treatment
The seeds were washed with distilled water, sundried, dehulled and allowed to pass through the different processing methods: (a) soaking in hot water for 12 hours (HWRSM); (b) soaking in ash solution for 12 hours (ASRSM); (c) roasting for 15 minutes and cooled at room temperature (RRSM); (d) Stored at room temperature for thirty five days (STRSM), (e) Chemical de-fattened using Sohlext apparatus (DRSM), while the last sample was unprocessed (URSM). The samples were dried, milled and chemically analysed. Proximate analysis of the samples was carried out using the AOAC method (AOAC, 2000).

Experimental treatments/samples for experiment
Based on the result of the chemical compositions , the two samples with best chemical compositions (RRSM and HWRSM) were selected for the experiment. Two hundred and fifty (250) day-old broiler chicks of Hubbard strain were purchased from AFGRI BnotHarel hatchery, Ibadan, Oyo-State, Nigeria. Out of which two hundred and ten (210) were selected for the experiment. The chicks were weighed and randomly allotted to seven dietary treatments. Each dietary treatment contained 30 chicks which were divided into three replicates of 10 chicks each. The birds/replicate was housed in floor of 3m x x 2.5m. The floor was covered with wood shavings as litter material. Each pen was equipped with feeding troughs and drinkers. The chicks were electrically brooded for two weeks. The experimental design for this experiment was completely randomized design with 2 by 4 factorial arrangement of two methods of processing (roasted rubber seed meal and hot water soaked rubber seed meal) and four levels of inclusion (0,15, 25 and 35%). Seven straight diets were formulated with equi-protein replacement of soybean meal with rubber seed meal (RSM) at graded levels. Diet 1 served as the control while diets 2, 3 and 4 contained roasted rubber seed meal (RRSM) at graded levels 15, 25 and 35% respectively, diet 5,6 and 7 contained hot water soaked rubber seed meal (HWRSM) at 15, 25 and 35% respectively ( Table 1). The birds were offered their respective diets during the period and drinking water of the experiment ad libitum. The chicks were given all routine vaccinations and necessary medications. The initial weights of the individual birds were taken at the commencement of the study and subsequent weight at weekly intervals to determine the weekly weight gain using cumulative analysis and final weight. So also the daily feed intake per replicate were recorded for the calculation of total feed intake and feed conversion ratio.

Data analysis
The results were used to assess the profitability of the test treatments. Data generated were analysed using SPSS ((16.0) software version, differences among the means were determined by Duncan's multiple range tests of the same package

III. RESULTS AND DISCUSSION
Growth performance of the birds fed graded levels of differently processed rubber seed meal (RSM) as shown in Table 2 revealed there were no significant (p ≥ 0.05) differences in all the parameters measured at all levels of inclusion. The final weight (2150.00-2243.07g), weight gained (2106.00-2213.60g), daily weight gained (50.14-52.01g) average feed intake (101.89 -108.46), average feed consumed (4177.67-4447.00g) and feed conversion ratio (1.91-2.10) were not significantly (p ≥ 0.05) affected by dietary treatments. Suggesting that soybean meal (SBM) and processed RSM have similar influences on the growth performance of broiler chickens. The fact that there were no significant variations in the treatments at all levels showed that rubber seed meal could be used to replace soybean meal in broiler chicken diets up to 35% equi-protein replacement level. This is agreement with earlier report on performance of pigs fed up to 30% replacement level of soybean meal with RSM (Eka et al., 2010). Treatments interaction was not also significantly differed, this mean that the two processing methods have similar influences on the performance of the birds. Therefore, roasting or soaking of rubber seed in hot water can be used to process rubber seed for broiler chickens.  chickens fed HWRSM performed significantly (P ≤ 0.05) better than their counterparts on RRSM based diet. Some parts weight (% eviscerated weight) and some relative organs weight (% live weight) measured as revealed in Table 4 and 5 respectively were not equally significantly (P ≥ 0.05) affected by dietary treatments. The weight reduces gradually as the levels of equi-protein replacement of soybean with RSM increased, this might be due to the presence of residual anti-nutritional factors and variations in the quality of protein in the ingredients (Akinsanmi et al., 2018). The similarity observed in the performance of birds fed control and test diets indicates that processed RSM based diet promote similar growth and organs development as soybean meal based diet and can therefore be incorporated into poultry chicken feed to replace scarce and expensive soybean meal by Nigerian poultry farmers.   Keys: SBM: soybean meal URSM: Unprocessed rubber seed meal, HWRSM: Hot water soaked rubber seed meal, RRSM: Roasted rubber seed meal, DRSM: Defatted rubber seed meal, ASRSM: Ash soaked rubber seed meal, STRSM: Store at room temperature rubber seed meal. SBM Soybean meal, NS: not significant.

IV. CONCLUSION
This study established the fact that equi-protein replacement of soybean meal in broiler chicken feed with graded levels of RSM from both processing methods [roasting and soaking in hot water] up to 35% did not have any noticeable adverse effects on the growth performance and carcass quality of the birds. This justify the call for the inclusion of processed RSM into the list of poultry feed ingredients as an alternative to scarce and expensive soybean meal.