Objective: The study aimed to assess Borassus aethiopum mature fruits’ dried pulp effect on growth performance and blood plasma lipids profile of Cobb 500 broilers. Materials and Methods: In this study 150 day-old Cobb 500 chicks were used, under a common starter diet for 3 weeks. Thereafter, 2 groups of 70 unsexed birds each were set. Data were collected weekly during grower and finisher phase, within a group, the weights were recorded by noting down the sex. The treatments were T0 (control diet, without Borassus aethiopum) and T1 (20% of the yellow corn was substituted by Borassus aethiopum ripe fruits dried pulp). At week7, 3 roosters fed on T0, 3 others fed on T1, 3 hens fed on T0 and 3 hens fed on T1 were slaughtered and the blood was collected for blood cell count and blood plasma lipids quantification. Results: Chickens fed on T1 diet showed lower growth performance. For example, weekly weight gain was 686.74 g in the male birds from T0 (MT0), whereas, male from T1 (MT1) had 532.86 g, thus a loss of 22.41%. Similarly, weekly weight gain in hens fed on T0 diet (FT0) was 502.48 g, while those from T1 (FT1) gained 458.14 g, thus 8.82% less growth performance. Regarding blood cells count, there was no significant difference between diets and sex, but the differences in plasma lipids profile were significant. Total cholesterol significantly declined from 128±4.31 (T0) to 109.17±4.31 mg dL1 (T1) (-18.83 mg dL1, p = 0.0042). Likewise, HDL decreased by 15%, from 64.86±1.37 to 55.13±1.37 mg dL1 (-9.73 mg dL1, p<0.0001). The LDL cholesterol decreased non-significantly by 17.19% from 46.93±4.02 to 38.86±4.02 mg dL1 (-8.07 mg dL1, p = 0.166). Conclusion: Borassus aethiopum mature fruits’ dried pulp can be incorporated into the diet of Cobb-500 broilers. It has no adverse effect. Moreover, it reduces the blood plasma cholesterols’ concentrations.
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In Ivory Coast, the transition zone landscape between the forest and the savannah is dominated by Borassus aethiopum trees1. Giffard2 observed that, roots of these plants are precious in traditional medicine, whereas the leafstalks are important in making roofs in the rural areas. The leaves and trunks are used by craftsmen to make baskets, beds and many other art works for house decorations. Unfortunately, an unsustainable economic activity such as making a sap wine on apical pod is dangerously causing the destruction of Borassus aethiopum forests3,4. By moving Borassus aethiopum forests away from the inhabitants’ areas, dropped mature fruits collection is becoming more and more difficult for women. Of course, sap wine collection practice ruins the activity of collecting the dropped mature fruits for hypocotyl production5, or for orange pulp flour productions1, by destroying the trees. Due to their high nutritive value in terms of sugars, vitamins and polyphenols6,7, the fruits are economically and nutritionally important. Unfortunately, industrial uses of Borassus aethiopum mature fruits for making wine are still limited. So, far away from habitats, a lot of dropped fruits are rotting in the wild. Mollet3 studied the Elaeis guineensis plants and reported that, when an important source of revenue is clearly established for a tree, people tend to grow this species and preserve its natural forests. The present study was conducted to assess the use of Borassus aethiopum mature fruits’ dried pulp in poultry feeds. So, the effect of Borassus aethiopum dried pulp on growth performance, the blood cells count and blood serum lipids profile of Cobb 500 broilers was determined.
MATERIALS AND METHODS
Diet preparation and broilers rearing: First of all, some Borassus aethiopum mature fruits were collected. Then, they were sorted and the undamaged fruits were stored for three or four additional days for better ripeness. Afterward, they were pilled and the fibrous pulp was removed and dried in ovens at 70°C until obtaining a constant weight7. Secondly, some dried yellow corn and commercial premix (Koudijs, Advanced Nutritional Products, De Heus Animal Nutrition, NL 14841, The Netherlands) for broilers were bought. During the first 3 weeks the chicks were fed on a starter diet. From week 4, the birds were allotted in two groups with two different diets (control and test diet) (Table 1). In T1, 20% of the yellow corn was substituted by Borassus aethiopum ripe fruits dried pulp.
Broilers rearing: A total of 150 day-old Cobb-500 broiler chicks were bought from a hatchery in Abidjan, Côte d’Ivoire. The birds were housed at the graduate school of agriculture experimental station, at the National Polytechnic Institute Felix Houphouet Boigny (INP-HB) in Yamoussoukro. Before their arrival day, The chicks’ house was prepared, sanitized and its floor was covered with wood chips and borders were covered with #46443D plastic to protect birds from cold air. At night time, rearing area of 15 m2 (5×3 m) was electrically heated with three electric lamps of 200 Watts each.
During daytime, electric lamps were turned off, the #46443D plastics were raised up so that the outside warm air could be circulated and this starter period lasted for 3 weeks.
Chicks were fed two times a day to avoid the wastage of mashed feedstuffs. The daily ration was divided into two portions,1/3 and 2/3 and they were given at 8 am and 4 pm, respectively. When the feed quantities of the day were completely consumed, then the last quantity per chick was increased by 5 g. During the starting period, five chicks died. In absence of an expert in chicks sexing, all chicks were sexed on day 21. Chicks were sexed by body feather cover method and were individually weighted. On day 21, the females had enough feathers on their wings and whole body compared to males. Moreover, compared to females, males’ crests were more developed. So that, the errors could be minimized.
Thereafter, they were transferred to the grower and finisher places and fed on 2 finishing diets (T0 and T1). Specifically, the chickens were raised on woods like traditional systems. So, the birds were not on the floor and all the birds’ droppings were below. Based on the average mean and standard error, five out layer birds were discarded from the experimental group. Thereafter, 140 remaining birds were randomly allotted in 2 groups of 70 chickens each and the diet test lasted for 4 additional weeks. Thus, the experiment covered 7 weeks in total.
From day 22-35, feed quantities were Increased step by step, the quantity per bird per day was stabilized on 130 g from day 36-49. Within a diet group, males and females were peaking together. But, from day 28-49, the birds were weighed, the data were recorded by considering the diet and the gender of each bird. The rearing area was 20.24 square meters (4.6×4.4 m = 20.24 m2) for each group. Thus, the chickens’ density was less than 4 birds per square meter. Then, on days 28, 35, 42 and 49 the chickens were weighed. From day 21-49, the chickens were fed only once at 12 O’clock. They were weighed before feeding. During all the experiments the birds had ad-libitum access to water.
Blood collection and its cells count: In each diet (T0 and T1), the two genders were considered. For data collection, 6 birds of similar weight (μ±δ, α = 0.05) (3 females and 3 males) were randomly selected per diet, a total 12 broilers. The birds were slaughtered and blood samples were collected into tubes containing some ethylene diamine tetra-acetic acid (EDTA) as anticoagulant9. The tubes were manually shaken to avoid the clots formation. The blood count was performed with a SYSMEX KX 21N hematology machine (Zhejiang Xinke Medical Technology Co., Ltd, Zhejiang city, China), at the national blood transfusion center in Yamoussoukro (Côte d’Ivoire). The hematological parameters such as hemoglobin (HGB), packed cell volume (PCV), red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cells (WBC), platelet (PLT), lymphocytes, monocytes, granulocytes percentage, respectively LYM%, MON% and GRAN% were analyzed.
Blood plasma lipids profile: During the growing and finishing periods, the chickens were fed one time at 12 O’clock each day. Then, the birds were slaughtered at 8 am for the blood collection using the Friedewald et al.10 approach. So, blood samples of birds were collected 20 h after the last meal. The blood was collected in dry tubes, containing clots activation agent, such as Factor XII (Hagemann Factor), kept at room temperature for 20 min for precipitation. Thereafter, it was centrifuged for 5 min. Then, the plasma was collected and stored in a refrigerator at 4°C. As soon as possible, the cholesterols’ contents reading was noted.
For total cholesterol assessment (Tot. C, Eq. 1), Cypress Diagnostics, (Ref: HB 006 Lot: 191 reagent, Hulshout, Belgium) was used11. So, to get the working solution, reagent 2 was poured in 1. Then, 1 mL of this working solution was put in each used graduated tube. Thereafter, the standard solution was made by pouring 10 μL of the standard solution in one tube, containing 1 mL of the working solution. Likewise, the blank was made by pouring 10 μL distilled water into each tube. Finally, 10 μL of the plasma was poured in each graduated tube, except in the blank and the standard. Then, the readings were proceeded by using a UV-visible spectrophotometer set at 500 nm (Shimadzu UV-1601 PC, Kyoto, Japan).
Again, following Kouassi et al.11 approach, for high density lipoprotein cholesterol (HDL.C, Eq. 2), Cypress Diagnostics was used, (Ref: HB 007 Lot: 322 reagent from Belgium). Only 1 mL of the plasma was mixed with 100 μL of HDL.C reagent. The newly gained medium was centrifuged. Then, 10 μL were collected and similarly for Tot. C steps, the preparations were done for readings. Finally, the cholesterol content was computed. Friedewald et al.10 equation was used to compute the low-density lipoprotein cholesterol (LDL.C, Eq. 4) content and the ratio of triglycerides over 5 is also known as the very low-density lipoprotein cholesterol (VLDL.C, Eq. 4). The results were expressed in milligram per deciliter (mg dL1). For triglycerides determination (Eq. 3), after preparing the corresponding working solution, the process remained the same as in Tot.C assessment. So, Tot.C, HDL. C and triglycerides absorbance were assessed by using a UV-visible spectrophotometer (Shimadzu UV-1601 PC, Kyoto, Japan) set at 505 nm.
where, 200 and 50 were the standard concentrations
After cholesterols and triglycerides analysis, blood plasma total protein was checked (Eq. 5). Also, Cypress Diagnostics was used (Ref: HB 0193 and lot TP 00331). Its working solution was previously prepared. So, the plasma was diluted in distilled water (DW), (Plasma/DW, 1/1, v/v). In this way, 200 μL of plasma was put in 200 μL of DW. Alike the previous steps, 10 μL of the newly made medium was collected and using the working solution, the samples were prepared for readings, using a UV-visible spectrophotometer (Shimadzu UV-1601 PC, Kyoto, Japan) set at 546 nm.
Statistical analysis: The weekly weight gain (WWG) was assessed through Excel trend line model, equation chart and r2 value on chart were displayed (Eq. 6). Thereafter, the weekly weight gain was determined using Eq. 6 first derivate. The confidence interval was set 95% for the examination of broilers’ live weight.
For blood plasma profile quantification, 2 blood samples were collected and 2 readings were made by sample. So, we got in total 4 readings for each combination (diet×gender) per chicken. Also, the data were submitted to a factorial analysis of variance (two-ways, ANOVA), using XLSTAT 2014. The least squares means were separated using Duncan’s multiple range tests. For hematological parameters and blood plasma lipids profile analysis (cholesterol, triglycerides and protein) the confidence interval was set at 99%.
RESULTS AND DISCUSSION
Broilers’ growth performance: For a given diet, the male broilers tended to grow faster than females (T0 versus T1, Fig. 1). For instance, from 4-7 week, T1 male broilers had a lower growth rate than those of the control group T0. Remarkably, the difference between these two groups of males was highly significant (p<0.0001). T0 (FT0, female birds) tended to grow faster than those of T1 (FT1, female birds, p<0.0001). Even if, 7 days after the diets test implementation (day 28), the weight differences between MT0 (1100.32±35.51 g), MT1 (1006.76±33.91 g) and FT0 (1003.29±30.88 g) were not significant, from week 5 (day 35) to week 7 (day 49), MT0 group showed higher weight than those of MT1 and FT0. Interestingly, all Excel derived models on growing curves were supported by equations with high coefficient of determination (r2>98.87%). With such goodness of fit, weekly weight gain (WWG) was deducted with the first derivative (Eq. 7).
Figure 1 shows that the weekly weight gain for MT0, FT0, MT1 and FT1 was 686.74, 502.48, 532.86 and 458.14 g, respectively. Similar result was reported by Panigrahy et al.12 who studied the growth performances of male and female broiler birds. Indeed, with Cobb-500 broilers, on day 28, Panigrahy et al.12 observed no significant difference in live weight between roosters and hens fed with the same diet. However, after day 28, males tended to grow faster than females, even with native chickens11. This tendency was already observed by Shim et al.13 who reported that on the day 48, after slaughtering commercial broilers, the males were heavier (3.57 kg) than females (2.98 kg).
Based on difference of live weight at 7th week between cocks (MT0 versus MT1, +590.12 g, +22.68%, p 0.0001) and hens (FT0 versus FT1, +198.46 g, +8.59%, p = 0.0283), it was noteworthy that dried pulp of Borassus aethiopum was well accepted by Cobb-500 broilers. Obviously, MT1 could not catch up MT0 because of the diet structure. Chewning et al.14 observed lower growth performance in birds fed with mash diet as compared to pellet or corn with particle size of around 0.3 and 0.6 mm. For example, Chewning et al.14 reported that mash, pellet and corn particle size of 0.3 and 0.6 mm led to body weight of 2,733, 3,227, 2,981 and 2,979 g, respectively in males and 2,239, 2,626, 2,440 and 2,415 g, respectively in females. Since 20% of the yellow corn was replaced by Borassus aethiopum dried pulp, thus density of T1 was reduced. So, this density reduction could explain the reason why MT0 birds grown faster than those of MT1. But male birds fed on low density diet T1 tended to grow faster than hens fed on high density diet T0. Therefore, it can be concluded that the hormones are more effective on sex dimorphism than diet. Numerically, MT1 grown faster than FT0, for 2601.67 versus 2510 g (+91.67 g, +3.52%). These weights were not statistically different (p = 0.2212).
Blood cells count: Table 2 shows the hematological qualities. Kuttappan et al.9 assessed white striation in broiler breast fillets and found no significant difference between treatments (T0 and T1). Nonetheless, the values of parameters were quite different from those of their normal chickens. Since they worked only on males. For example, the white blood cells (WBC), in the present study was 43.83 and 45.07×103 μL1, for MT0 and MT1, while Kuttappan et al.9 found the value 24.04×103 μL1 for white blood cells. For body immunology, WBC count observed in the current study (44.45×103 μL1) was higher (84.90%) than that noted by Kuttappan et al.9.