Department of Animal Science, Faculty of Agronomy and Agricultural Sciences, University of Dschang, Dschang, Cameroon; ^*Corresponding Author: cyralex2000@yahoo.fr

Copyright © 2013 Cyrille D’Alex Tadondjou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received 5 July 2013; revised 20 September 2013; accepted 1 October 2013

Keywords: Energy; Body Weight; Testes; Semen; Puberty; Local Barred Chicken

ABSTRACT

This study was designed to examine the effects of dietary energy levels on some growth and reproductive parameters of local barred chickens in Cameroon. For this purpose, One hundred and forty four day-old barred male chicks, weighing 28.33 g in average were randomly divided into 12 groups of 12 chicks each. Three feeding programs (FP) comprising each a starter diet from day old to 12 weeks (S0: 2800 Kcal/Kg; S1: 2900 Kcal/Kg; S2: 3000 Kcal/Kg) and grower diet from 13 to 20 weeks (G0: 2900 Kcal/Kg; G1: 3000 Kcal/ Kg; G2: 3100 Kcal/Kg) were used and designated FP1, FP2 and FP3 respectively. Each of the FP was randomly allotted of 4 groups of 12 birds in a completely randomized design. Throughout experiment (1 day old to 20 weeks), body weight was recovered every 2 weeks. At 20 weeks of age, roosters were sacrificed; semen characteristic was analyzed and testes were characterized. Between 2 to 10 weeks old, body weight of cocks fed with FP3 was significantly higher (P < 0.05) as compared to others FP. Inversely, from 12 to 20 weeks, body weight of cocks receiving FP1 was significantly higher (P < 0.05) than that of cocks receiving feeding programs 2 and 3. At 20 weeks, 100% of cocks fed on FP3 produced semen versus 66.66% and 16.66% respectively for those on FP1 and FP2. Semen volume and mass motility of cocks fed on FP3 or FP1 were significantly (P < 0.05) higher than FP2. It was concluded that FP1 had more suitable dietary energy levels for growth and reproduction of local barred cocks.

1. INTRODUCTION

Local chickens are characterized by good adaptability to the hard tropical environment, slower growth rate, poor laying ability and smaller egg size compared to the exotic breed; In addition, they possess good mothering ability and resistance to diseases [1]. In developing countries, many studies attempted to evaluate the genetic potential of the indigenous birds under improved management conditions [2-7]. Most of works tended to overlook behavioral and reproductive traits, which are important under village production environment [1]. However, one of the most important objectives of poultry breeding in village condition is the production of chicks since they are highly demanded in the market. Chick’s production highly depends on flock fertility. As it has been reported, semen quality can impact egg fertility and subsequently egg hatchability [8]. According to Sarah [9], fertility in a breeder flock can be improved by using males with high sperm quality. Upendra et al. [10] reported that semen quality is positively correlated with percentage of fertile eggs and hatchability. The semen quality in poultry gives an excellent indicator of their reproductive potential [11, 12]. Usually, assessing fertilizing potential of semen includes sperm morphology, motility, concentration, viability, ability of acrosome to penetrate oocytes, the specific conductivity of the ejaculate [13,14]. However, sperm viability, concentration and motility are the major components of routine quality assessment [12,14]. These components are under the control of many factors including feeding.

Dietary energy level has been reported by many authors to affect performance trait such as body weight, delayed sexual maturity, semen production and quality in the male bird [15-17]. It has been reported that hypoenergetic diet leads to excessive weight gain [17,18] and consequently induce early sexual maturity and reduce fertility in male broiler [17]. Kirby et al. [19] reported that increase in calorie intake may lead to an increase in testes weight with no apparent increase in spermatogenic efficiency. Adequate nutrition is therefore essential to maintain the breeding flock in good reproductive condition [17]. Age at sexual maturity has long been considered as an important factor that determines fecundity trait and affects subsequent performances [20-22]. In cock flock, Brière et al. [17] reported that sexual precocity is related to early testicular regression. Kirk et al. [23] and Walsh and Brake [24] revealed that one of the major problems encountered with commercial broiler breeder flocks has been the often dramatic decrease in fertility during the latter part of laying period, particularly after 50 weeks of age. This could be associated with decrease in semen quality. Several studies on semen characteristics of African local cocks have been published [25,26] but none of them reports on Cameroon chickens which constitutes approximately 56% of the chicken population in the country [27]. Moreover, there is no information on nutritional requirements of these birds. The aim of the present study was therefore to evaluate the effect of dietary energy level on body weight, testicular development and semen characteristic of local barred cocks of the Western Region of Cameroon.

2. MATERIALS AND METHODS

2.1. Study Area

The study was carried out between February and September 2012 at the Teaching and Research Farm of the University of Dschang (LN 5 to 7˚, LE 8 to 12˚). Dschang is located in the Western Sudanoguinean Savanna of Cameroon at 1500 m above sea level. Mean wind speed is 1.60 m/s; mean temperature is 20˚C and relative humidity generally exceeds 60%. Annual rainfall varies between 1910 and 2010 mm. The raining season goes from mid-March to mid-November and the dry season from mid-November to mid-March.

2.2. Experimental Animals

One hundred and forty four day-old barred male chicks, weighing 28.33 g in average were randomly divided into 12 groups of 12 chicks each. Chicks were housed in raphia bamboo made cages and kept under similar environmental and managerial conditions during experiment. Feed and water were given ad libitum in adapted equipments.

2.3. Experimental Diets and Design

Three feeding programs comprising each a starter diet from day old to 12 weeks (S) and grower diet from 13 to 20 weeks (G) were drawn as reported in Table 1.

Each of the feeding programs was randomly allotted of 4 groups of 12 birds in a completely randomized design.

2.4. Data Collection

Live body weight was recorded every two weeks.

At 20 weeks of age, 8 cocks per treatment were randomly chosen and sacrificed by decapitation. Semen was collected immediately after sacrifice by slight finger pressure on spermiductus from epididymalductus till the base of the phallus. The number of cocks producing semen was recorded together with volume and color of the

sample. The collected semen was maintained at 38˚C - 40˚C using a water bath for sperm motility assessment and sperm density. The left and right testes were also removed, cleaned from adhesive tissue, and testes measurements were recorded. The left testis diameter and height were measured. The testicular shape index was obtained by dividing testicular diameter by testicular height.

The collected semen was analyzed as described by Ngoula et al. [28] and Hafez [29].

2.5. Statistical Analysis

Data collected were subjected to one way analysis of variance (ANOVA) at P < 0.05. When differences were significant between means, Duncan multiple range test were used to separate means. Pearson correlation coefficient for some parameters was also performed at P < 0.05. All statistical analyses were performed using SPSS 12.0.

3. RESULTS

3.1. Effect of Dietary Energy Level on Body Weight

Figure 1 presents the evolution of live body weight of cocks during the experiment. Between 2 and 10 weeks, body weight of cocks receiving feeding programs 3 (FP3) was significantly higher (P < 0.05) than that of animals