The guinea fowl are a group of birds that make up both domestic and wild birds, and are known to be native to the African continent (Adjetey et al., 2014). The helmeted guinea fowl (Numidia meagris) has been commercially widely used, with common varieties that include the pearl gray, lavender, royal purple and white helmeted guinea fowl. There are a major source of animal protein in resource-poor communities and thus play a critical role in ensuring   food   and  nutrition  security  (Ebegbulem  and Asuquo, 2018). However, there are known for their hardiness, low production costs, greater capacity to utilize green feeds, and are generally resistant to most endemic poultry diseases (Moreki and Seabo, 2012).

Strategies that enhance productivity of guinea fowls include improving their nutrition and cross breeding. Cross breeding combine different characteristics of different breeds (Getu and Birhan, 2014). In poultry, the hybrid fowl have been observed to be more uniform  than most standard breeds, except for colour in some crosses, while the vigor and productivity of the hybrid were superior to original breeds or breeds of origin (Egahi et al., 2013). Mohammed and Abdalsalam (2005) showed that cross breeding also improve body weight gain in poultry species. On other hand, Ebegbulem and Asuquo (2018) found no significant difference in growth performance and carcass characteristics between pure and crossbred guinea fowls. These conflicting reports suggest that further studies are necessary to determine growth performance of different guinea fowl varieties and their crosses.

In Botswana the amount of meat produced by guinea fowls is unknown as the production of birds is unregulated and unstructured (Moreki and Seabo, 2012). Enhancing the productivity of these birds is, therefore, imperative if food and nutrition security in Botswana communities are to be guaranteed. However, there is currently limited information on the growth performance of royal purple and white guinea fowl varieties and their crosses under an intensive management system in Botswana. This study was, therefore, conducted to evaluate growth performance of crossbred royal purple x white guinea fowl relative to the purebred royal purple and white varieties under an intensive management system.

Description of the study site

This study was conducted from October to December 2017 at the Botswana University of Agriculture and Natural Resources (BUAN) Content Farm, Sebele, Gaborone. BUAN is located at 25.94°S, 24.58°E at altitude of 991 m. During this time, the mean ambient temperature was 35°C.

Experimental animals and feeding

Five royal purple guinea fowl (RPGF) males were housed together with 30 White guinea fowl (WGF) females in one deep litter house to produce fertile eggs. Another five royal purple males were housed together with 30 pure-bred royal purple females and five white males were housed together with 30 pure-bred white females in three separate houses to produce fertile eggs. Hundred  and  fifty eggs were collected from each of the three guinea fowl houses and incubated in an automatic egg incubator at 37.5°C and 65% relative humidity for 28 days to produce cross-bred and pure-bred keets. Upon hatching pure-bred and cross-bred (CBGF) keets were housed separately in brooding units until 3 weeks of age. At four weeks of age, the guinea fowls were individually identified using leg bands. Twenty pure-bred white, 20 pure-bred royal purple and 20 cross-bred guinea fowls were housed together in a guinea fowl house for a total of 4 houses, resulting in 4 replications. The guinea fowls were fed commercial broiler starter crumbs from day old to 4 weeks of age, and thereafter fed commercial broiler grower pellets until the end of the study. Both commercial feeds (Table 1) were bought from Nutri feeds PTY, Ltd, Pilane, Botswana.

Measurement of parameters

The guinea fowl were weighed individually at the beginning of the experiment and thereafter on a fortnightly basis from 4 to 16 weeks, using an Adam 6010 model electronic balance (Adam, Gaborone, Botswana).

Statistical analysis

Growth data were analyzed using General Linear Model procedures of statistical analysis system SAS (2009). The model included fixed effect of variety (royal purple, white and crossbred royal purple x white) and sex (male and female) and the interaction between variety and sex.  Results on the effects of variety, sex and the interaction between variety and sex are presented as least squares means±SE. Means separation were by paired t-test with Scheffe’s adjustment to account for differences in guinea numbers within sex and differences between means were separated at α-level of 0.05.

There were no significant differences between body weights of males and females of the three varieties at all ages (Table 2). There was, however, an increase in body weight among all the varieties from 4 weeks of age up to 16 weeks of age.

Main effect of strain (combined average body weight of both males and females) on body weight in purebred royal purple and white varieties and crossbred royal purple x white varieties at different ages are presented in Table 3. There were no significant body weight differences (P>0.05) among the three guinea fowl varieties from 4 to 8 weeks of age. There were also no significant weight differences between purebred royal purple and cross-bred royal purple x white guinea fowl from 10 to 16 weeks of age. Royal purple guinea fowl were, however, significantly heavier than their age-matched white counterparts from 10 to 16 weeks of age. Cross-bred guinea fowls were significantly heavier than their white counterparts only at 16 weeks of age. Crossbred guinea fowl were, however, heavier than their white counterparts at all ages from 4 to 16 weeks of age. The royal purple guinea fowls were also heavier than their aged-matched crossbred counterparts from 10 to 16 weeks of age. Crossbreeding was thus effective in improving the growth performance of the white guinea fowl variety but crossbred guinea fowls were out-performed by the royal purple variety. This suggests that the royal purple variety should be promoted as the meat type guinea fowl variety in Botswana.

Cross-breeding was evaluated as an alternative method of improving growth performance of different varieties of guinea fowls. Cross-breeding was effective in improving growth performance of the white variety but had no beneficial effect on the growth performance of royal purple variety. The royal purple variety proved  to  be  the best variety in terms of growth performance and is therefore the most recommended variety for meat production in guinea fowls.

The authors have not declared any conflict of interests.