Citation of this paper

Performance and lipid profile of growing pigs fed Vernonia amygdalina and Jathropha tanjorensis leaf meal supplementation

Ekpo J S and Okon U M

Department of Animal Science, Akwa Ibom State University, Obio Akpa Campus, Akwa Ibom State, Nigeria
jsekpo2000@gmail.com

Abstract

A total of sixteen grower pigs were used to evaluate the effect of Vernonia amygdalina and Jathropha tanjorensis leaf meal supplementation on their performance and lipid profile. The animals were randomly allotted to 4 dietary treatments with 2 replicate per treatment. The treatments were arranged as follows CTL₁ (basal feed only),VM4 VM4 (basal feed + 4% VALM), JM4 (basal feed + 4% JTLM) and VM2JM24 (basal feed + 2% VALM + 2% JTLM) in a completely randomized design. The study lasted for 56 days. At the end of the feeding trial, blood samples were randomly collected from 8 pigs (2 per treatment) to determine the lipid profile (total cholesterol (TC). triglyceride (TG), low density lipoprotein (LDL) and very low density lipoprotein (VILDL). Result showed an increase (p<0.05) in feed intake and daily weight gain of the animals. Pigs in JM4 group recorded the best feed intake, weight gain and feed conversion ratio. Lipid profile indices of the growing pigs also indicated a reduction in total cholesterol, triglycerides, low density lipoprotein and very low density lipoprotein, with a corresponding increase in high density lipoprotein across treatments. Supplementing pig’s diet with Vernonia amygdalina and Jathropha tanjorensis leaf meal improved (p<0.05) the performance and lipid profile. It is therefore recommended that Jathropha tanjorensis leaf meal (JTLM) can be added to the diets of pigs at 4% body weight supplemental level for optimum performance and improved lipid profile.

Key words: Jathropha tanjorensis, lipid profile, performance, pigs, Vernonia amygdalina

Introduction

Nigeria is reported to rank second in pig population in Africa and pig meats contribute about 4.5% of meat consumption in Nigeria (Adinya et al 2012). The abundance of feed resources, especially farm residues and agro industrial by-products, therefore gives the country a comparative advantage for pig production. In recent years considerable attention has been given to the improvement of meat quality (Swigert et al 2004). Pigs have shown great potential in contributing to the nation’s economic gains because they have a short gestation period, high fecundity and farrow between 6-15 piglets depending on breed (Lekule and kyysgaard 2003). The search for least cost rations due to the increasing competition between man and animals for available grains has led to the replacement of expensive feedstuff with cheaper alternative in monogastric nutrition. Some of these are obtained from industrial by-products and agricultural wastes like maize offal, soya beans hull, cowpea hull etc. The realization that feeding alone currently account for over 75% of intensive non-ruminant (poultry and pig) production in the third world countries, including Nigeria had stimulated research interest aimed at exploiting different locally available alternative feed resources (Agbede and Aletor 2003). Plants usefulness to man is not only as sources of raw materials for industries, but also as source of food and medication. From earliest times, plants have provided man with diverse means of healing. Two of such plants suspected to have therapeutic as well as nutritional values are Vernonia amygdalina and Jatthropha tanjorensis. Vernonia amygdalina has been reported by Ekpo et al (2022a) to contain polyunsaturated fatty acids, linoleic acid as well as antioxidants which could boost high density lipoprotein (HDL) while reducing low density lipoprotein (LDL) and total cholesterol. The bioactive properties inherent in both plants make them a good fit in the prevention of accumulated lipids and cholesterol in meat. Vernonia amygdalina is green in colour with a quality odour and bitter taste. It is so unique that every part of it is economically important. The plant contains significant quantities of antioxidants (Ejoh et al 2007), protein and essential amino acids, carbohydrates (Eleyinmi et al 2008) and little quantity of carotenoids and minerals (Udensi, et al 2002; Bonsi 1995). Jathropha tanjorensis is a plant that originated in Mexico and spread widely in tropical and subtropical areas including Africa (Dias et al 2012). The seeds of the plant generally contain toxic components but produce 24 - 40 % oil, rich in palmitic acid (16:0,13.4 - 15.3 %), Oleic acid (18:1, 34.3 - 45.8 %), and linoleic acid (18:2, 29.0 - 44.2 %) (Meher et al 2013). This study was therefore conducted to evaluate the effect of Vernonia amygdalina and Jathropha tanjorensis leaf meal supplementation on performance, carcass and lipid profile of growing pigs.

Materials and methods

Experimental Site

Experiment was conducted at the Piggery of the Teaching and Research Farm of Akwa Ibom state University, Obio Akpa Campus. The area is situated between latitude 5^o17'N and 5^o27'N and longitude 7 ^o21'E and 7^o58'E with annual rainfall from 3500 – 5000mm, monthly temperature range of 24 – 26^oC and relative humidity between 60 – 90 % (AKSU-MET 2016).

Experimental materials sourcing and processing

Leaves of Jathropha tanjorensis (commonly known as hospital is too far) and Vernonia amygdalina (bitter leaf) were sourced from farms in Abak Local Government Area of Akwa Ibom State, Nigeria. The leaves were air dried for 24 hours before being chopped into smaller sizes and mixed as supplement in the diet. Quantity of the chopped leaves in diet was 5 % of the animal’s body weight.

Experimental diet

Four experimental diets were formulated such that treatment one (CTL) with no test material served as control, diet 2 and 3 which containedVernonia amygdalina leaf meal (VALM) and Jathropha tanjorensis leaf meal (JTLM) respectively at 4 % of the pig’s body weight served as VM4 and JM4_.Treatment 4 (VMJM2) contained 2% each of VALM and JTLM. Feed and clean water was given ad libitum twice a day (8am and 4pm) to the animals. The two leaf meals were added as an inclusive part of the calculated experimental diets according to NRC (1998) as shown in Table 1.

Table 1. Gross Composition of the experiment diets
Ingredient	CTL	VM4	JM4	VM2JM2

Maize	45.00	45.00	45.00	45.00
Soybeans	16.00	16.00	16.00	16.00
Palm Kernel Cake	16.60	16.60	16.60	16.60
Wheat Offal	19.40	18.90	18.90	18.90
Bone meal	2.25	2.25	2.25	2.25
Vitamin Premix	0.25	0.25	0.25	0.25
Salt	0.50	0.50	0.50	0.50
Total	100.00	100.00	100.00	100.00
Calculated Composition
Crude Protein (%)	21.48	21.48	21.48	21.48
Crude Fiber (%)	1.01	1.01	1.01	1.01
Crude Fat (%)	5.34	5.34	5.34	5.34
Ash (%)	4.70	4.70	4.70	4.70
Gross Energy (Kcal/Kg)	2901	2901	2901	2901

Experimental animals, management and design

Sixteen (16) large white growing pigs were acquired from the Piggery unit of the Department of Animal Science, Akwa Ibom state University, Obio Akpa Campus and used for the experiment. The pigs were weighed at the start of the trial and their weights equalized before being allotted to different treatment groups. Initial body weight and weekly body weights were also taken subsequently until the end of the experiment. Routine cleaning of the pens was observed throughout the period of the experiment. The experiment was laid in completely randomized design.

Proximate analysis of test materials

Sample of the leaf meals were taken to the laboratory for proximate analysis according to methods described by AOAC (2003).

Growth performance

The initial weight of the pig was taken at the beginning of the experiment and subsequently on weekly basis using a weighing balance. The live weight gain was calculated as the difference between previous weight and weights recorded in the following week. This was taken at an interval of seven days for the period of 56 days. The feed intake per pig per day was calculated as the difference between feed offered and spilled/left over feed (after 24 hours of feeding). The feed conversion ratio was calculated as ratio of feed intake to weight gain using the formula: Feed conversion ratio = feed intake/weight gain

Lipid profile determination

A sample of 5 ml of blood was collected from the marginal vein of the ear of each of the 2 pigs per treatment for serum lipid determination at the end of the experiment (56^th day). The blood were collected into plane bottle (without anticoagulant) and centrifuged at 3000 rpm for 15 minutes. The serum was used for lipid determination based on the method described by Baker et al. (1998). Parameters assessed included triglyceride (TG), Total cholesterol (TC), low density lipoprotein, high density lipoprotein (HDL-C) and very low density lipoprotein (VLDL).

Data analysis

All data collected were subjected to Analysis of Variance (ANOVA) procedure of Statistical Package for Social Sciences (SPSS 2007). Significant differences were separated using Duncan’s Multiple Range test (Duncan 1955).

Results and discussion

Proximate analysis of test ingredient

The result of proximate composition of experimental diets is presented in Table 2. The result indicated that VMJM2 had the highest value for crude protein followed by JM4, while CTL had the least. The crude fibre content of VM4 recorded the highest value followed by JM4 while CTL had the least. Ether extract was higher in VMJM2 while VM4 had the least value. The ash content indicated a higher amount of ash in VM4 followed by JM4 and the least value obtained in CTL. The values of ether extracts, nitrogen free extracts and metabolizable energy obtained in this study for VALM were within range reported by (Ekpo et al 2022a; Ejoh et al 2007). Likewise, the ash and nitrogen extract obtained for JTLM is comparable to values reported by Egbon et al (2013). The slight differences in the nutrient composition may be attributed to varietal and geographical differences. Report by Ekpo et al (2020) indicated that geographical and varietal differences are the fundamental causes of differences in nutrient composition of plants.

Table 2. Proximate and Gross Energy composition of experimental diets
Sample	CTL	VM4	JM4	VM2JM2

Dry matter	87.69	87.16	86.98	83.13
Crude protein	14.37	14.69	14.88	15.07
Ether extract	2.59	2.78	2.89	2.95
Crude fiber	3.87	4.13	4.05	3.93
Ash	3.48	3.69	3.57	3.52
NFE	63.38	61.87	61.59	61.48
G.E(Kcal/kg)	2,829	2,862	2,873	2,885
NFE = Nitrogen Free Extract; G.E = Gross Energy

Table 3 presents the results of dietary supplementation of JTLM and VALM on the performance of growing pigs. The result showed that pigs fed VM4, JM4 and VMJM2-based diets recorded an improvement (p<0.05) in daily feed intake except for those in CTL (control). The increase in feed intake could be attributed to increasing fibre level of Treatments 2, 3, and 4 compared to CTL (control). Ekpo et al (2019a) in a research with grower pigs fed pumpkin stem waste and cassava leaf meal, reported significant improvement in feed intake due to higher fibre. In addition, the test materials are rich in antioxidant properties. This is suspected to contribute to the increased feed intake. This is in line with Okon et al (2022) and Selim et al (2008) who reported that dietary antioxidants increased voluntary feed intake on rabbits and poultry respectively. Weight gain indicated that the animals were positively influenced (p <0.05) by the experimental diets. Pigs fed 4% inclusion of JTLM had the highest daily weight gain of 0.22 kg compared to CTL (0.21 kg), VM4 (0.17 kg) and VMJM2 (0.16 kg). The higher values (p <0.05) in weight gain observed in the JM4 group may be attributed to the high feed intake of pigs in JM4 as well as the increased protein and Ether extract content. It is worthy of note that dietary antioxidants present in JM4-based diet could also increase digestibility. Thereby resulting in improved weight gain in the pigs as observed. The values of weight gain obtained in the study is comparable to values reported by Ekpo et al (2022b) on pigs fed cassava leaf meal, pumpkin stem and moringa leaf meal as supplements. However, the lowest weight gain observed in VMJM2 Suggests the effect of increased anti-nutrients due to combined effect of anti-nutrients from Jatropha tanjorensis and Vernonia amygdalina. Feed conversion ratio differed (p <0.05) among treatment diets. The lowest and best value was obtained in JM4 followed by CTL and VMJM2 while the poorest feed conversion ratio was obtained from VM4. This implies that pigs in JM4 group were able to efficiently convert feed to meat. The poor FCR of VM4 may be due to some anti-nutrients such as tannins suspected to be higher in bitter leaf.

Table 3. Growth Performance of pigs fed VALM and JALM
Parameters	CTL	VM4	JM4	VM2JM2	SEM

Initial body weight (kg)	25.00	25.00	24.50	24.25	1.84
Final body weight (kg)	36.50^a	35.50^ab	33.00^ab	31.50^a	0.96
Total Weight gain (kg)	11.76^b	9.50^d	12.32^a	8.96^c	0.46
Daily weight gain (kg)	0.21^b	0.17^c	0.22^a	0.16^d	0.008
Total feed intake (kg)	7.00^b	72.80^a	72.80^a	72.80^a	1.55
Daily feed intake (kg)	1.20^b	1.30^a	1.30^a	1.30^a	0.027
Feed conversion ratio	5.95^c	7.64^a	5.90^bc	7.28^ab	0.35
^abc means on the same row with different superscripts are different (p<0.05)

Effect of Jatropha tanjorensis and Vernonia amygdalina on Lipid Profile of Pigs

The results of Total Cholesterol (TC), High Density Lipoprotein (HDL), low density lipoprotein (LDL), triglyceride (TG) and very low density lipoprotein (VLDL) are presented in Table 4. The results indicated that TC, LDL, TG, VLDL and HDL were significantly affected by the experimental diets. CTL recorded the highest total cholesterol value compared to other treatments. The reduction in LDL, TC, TG and VLDL as well as increase in HDL for pigs in JM4 followed by VM4 showed the lipid reducing property of Jatropha tanjorensis and Vernonia amygdalina. This may be attributable to some bioactive substances present in these test materials. This agrees with Ekpo et al (2019b) who reported that antioxidants can reduce LDL, TC, TG and VLDL while increasing HDL in rabbit. Secondly, the higher fiber content of VALM and JTLM must have contributed to the reduction in TC, TG and LDL as observed.

Table 4. Effect of Jatropha tanjorensis and Vernonia amygdalina on lipid profile of pigs
Parameters	CTL	VM4	JM4	VM2JM2	SEM

Total Cholesterol	144.55^a	140.00^ab	132.10^b	122.21^c	2.76
High Density Lipoprotein	54.09^a	57.97^a	60.15^a	53.65^b	0.88
Triglyceride	129.68^a	112.99^c	119.51^b	125.55^a	2.05
Low Density Lipoprotein	66.56^a	59.47^b	46.02^c	43.45^c	3.01
Very Low Density Lipoprotein	25.93^a	22.56^c	23.90^b	25.11^a	0.41
^abc means across the treatment bearing different superscript are different (p<0.05)

Conclusion

This study revealed that inclusion of Jathropha tanjorensis (JTLM) at 4% body weight in pig significantly increased weight gain feed intake and feed conversion ratio compared to other diets.
The test materials also significantly reduced low density lipoprotein, total cholesterol, triglyceride and very low density lipoprotein while increasing high density lipoprotein (HDL) of pigs.
It is therefore recommended that Jathropha tanjorensis leaf meal (JTLM) can be added to the diets of pigs at 4% body weight supplemental level for optimum performance and improved lipid profile.

Acknowlegement

The authors appreciate the Department of Animal Science Teaching and Research Farm, Akwa Ibom State University for granting the permission to use its facility.

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