MATERIALS AND METHODS

Study area
Experimental housing and management: The study was carried out at Poultry Research Unit, Faculty of Animal Production, University of Khartoum, Sudan from September to November, 2020 during the time of the experiment, the ambient temperature ranged from 26.5-37.6. The experiment was carried out in an open-sided deep litter poultry house. Four inches thick layer of wood shaving material was laid on the floor of each pen with the allocation of on tubular feed trough and one round fountain drinker, the light was provided for 24 hrs.

Experimental birds: One hundred twenty-eight, one-day-old, unsexed (hybrid) broiler chicks were randomly divided into 4 groups of 32 chicks. Each group was further subdivided into replicates with 8 chicks per pen. For experimental diets were formulated to evaluate the nutritive value of Roselle seed for broiler chicks as a source of protein graded levels of Roselle seed were added, being: 0.0, 5, 10 and 15% (on a dry matter basis) to the basal diet. The ingredients and chemical composition of the experimental diets are presented in Table 1 and 2.

Growth performance
Feed intake: Total feed offered and residue for each pen were recorded daily to calculate group feed intake by difference.

Live weight gain: The chicks were weighed weekly using a spring balance. Mortality rates and temperatures were recorded throughout the experimental period. At the end of the experimental period, five birds from each replicate were selected randomly, weighed individually, live and hot carcass weight.

Experimental design and statistical analysis: The experiment was conducted using a complete randomized design. Data obtained (feed intake, body weight gain and feed conversion ratio) were tabulated and subjected to Analysis of Variance (one-way ANOVA) using the GLM procedure of SAS⁵. The differences between treatment means were determined using Duncan's Multiple Range Test.

RESULTS AND DISCUSSION

Effect of dietary Roselle seeds on broiler performance: The date of average feed intake, body weight gain and feed conversion ratio are summarized in Table 3. Feed consumption increased with an increasing level of Roselle seed in ratio. The group 15% high-level seed consumed more feed (3145.00 g/chicks) than that consumed by group 5% lower Roselle (2889.00 g/chicks). The average body weight at the end of the experimental period showed no significant difference (p>0.05). Performance of broiler chicks in terms of feed consumption, feed conversion and live weight gain showed that the addition of Roselle seeds increased feed consumption with significant results in the 1st and 2nd weeks. Dietary Roselle seed has no significant effect on live body weight (p>0.05). There was no increase in the level of Roselle in diet so the heavy birds were in the group (5% low Roselle to (1338 g) birds in the group (15%) content gained weight (1323 g).

Feed intake: Date showing the effect of feed graded levels of Roselle seeds Hibiscus sabdariffa on weekly feed intake is presented in Table 4 the result revealed that the dietary treatment had a significant effect in the 2nd week, (p<0.05) on feed intake in 10% (Roselle) improved feed intake compared diet during the 2nd week. The data showed that week's first, third, fourth, fifth and sixth had no significant effect on feed intake. The result in these tables showed that feed intake was increased by increasing levels of seed (5, 10 and 15 %) were significantly different (p<0.05) improved feed intake during the 2nd week. This result agreed with⁶. Broiler breeder males showed lower apparent digestibility of Roselle in the 1st week of life than the 2nd and 3rd weeks of the edge. This variation may be due to the chemical composition of Roselle seed used in this study indicated that it contained higher crude protein (30.26%) than the values of 23.8 and 25.2% reported earlier by Owosibo et al.⁶ and Ismail et al.⁷, who reported protein content levels of 23.8 and 25.2%, respectively. Similarly, the crude fibre content observed in this study was also higher than levels reported by the same authors. The discrepancies might be attributed to the variety of Roselle seeds, geographical location or methods of processing.

Bodyweight: Bodyweight gain data is given in Table 5 showing weekly weight gain as affected by the addition of Roselle to the diet. Birds fed 0% Roselle grew better than those fed higher levels of Roselle (15%). Bodyweight gains were not significantly affected during the last week. Improved body weight gain, was similar to the results of the previous studies⁸. This positive response may be related to the reduction of the fibre content of the Roselle level. The reduction in feed intake may be due to the bitter taste resulting from the saponin content of the raw roselle seed meal⁹. They attributed the effect to the acid test of Roselle that might interfere with the palatability of rations. The poor body weight gain of chicks fed 10 and 15% Roselle observed during the first 3 weeks may be related to the poor feed consumption observed during this period.

Feed conversion ratio: Table 6 shows feed conversion/g, feed consumed/g and body weight gain/g as affected by the addition of Roselle seeds. Data collected showed that feed conversion ratio decreased with increasing level of Roselle seed in diets and with increasing age of chicks (2.20, 2.16, 2.23 and 2.41), respectively for the four treatments, these findings were agreed with results reported earlier^9-12, affected by increasing of Roselle seed during the whole period, had no significantly different effect. During 6 weeks experimental period, feeding graded levels of Roselle had no significant effect on feed conversion ratio. The influence of dietary treatments on chick's weight gain, feed intake, feed conversion ratio and final body weight Although chicks consuming the control diets showed relatively higher weight gain, none of the treatments had a significant effect on any of the measured parameters.

Internal organs: Table 6 illustrates the effect of dietary Roselle seeds (Hibiscus sabdariffa) on weights of internal organs and percentage (g). Dietary treatments had no effects on internal organs such as the liver and spleen, which is in line with the previous reports¹³.

Overall, the use of Roselle seed as a protein source for broiler chicken up to 15% without any adverse effect, suggesting that Roselle seed could be a local, low cost and available alternative protein source for the poultry industry replacing other high-cost sources like fish meal and meat meal. More research is required to investigate meat quality and the economical value of replacing conventional protein sources with Roselle seeds in broiler diets.

CONCLUSION

The results have shown that the inclusion of Roselle (Hibiscus sabdariffa) seeds in broiler diets up to 15% had no adverse effect on feed intake, feed conversion ratio, growth performance, carcass characteristics or internal organs.

SIGNIFICANCE STATEMENT

This study discovered that the Hibiscus sabdariffa seeds could be added to broiler's diets as an alternative protein source. Although the highest level used in this study had no significant effect on the growth performance of broilers, however, this study will help the researchers to reveal locally available protein sources for broiler chickens.