Citation of this paper

Effect of cassava leaves (Manihot esculenta Crantz), water spinach (Ipomoea aquatica) and Coccinia grandis L. on biomass growth of crickets (Gryllus bimaculatus) fed chicken feed as the basal diet

Bui Phan Thu Hang, Nguyen Van Cop and Vo Lam

Department of Animal Sciences and Veterinary Medicine, An Giang University Vietnam National University Ho Chi Minh City, Vietnam
bpthang.agu@gmail.com

Abstract

Seven thousand and two hundred crickets (Gryllus bimaculatus) with a mean initial weight of 11.3±0.66 mg/cricket and an age of 7 days were housed in ages (300 per cage) and offered a basal diet of chicken feed alone, or supplemented with leaves of sweet cassava (Manihot esculenta Crantz), water spinach (Ipomoea aquatica) or Coccinia grandis L. The design was a randomized block with 4 treatments (sources of leaves) and 6 replications (300 crickets per treatment/replicate).

Over a period of 28 days, the total biomass yield of crickets was increased by 14% when they had free access to fresh cassava leaves as well as commercial chicken feed. When leaves from water spinach and Coccinia grandis were offered as supplements they were consumed in smaller quantities, as compared with cassava leaves, and there were no benefits in biomass growth of the crickets compared with access to chicken feed alone.

Key words: cassava leaves, feed conversion, fresh foliage, weight

Introduction

In developing countries, children often suffer from protein-energy malnutrition (UNICEF 2012). Malnutrition and undernutrition in Vietnamese children have been identified as a problem. Chaparro et al (2014) reported that in Vietnam the proportion of children under two years old, whose diet meets the minimum standards for dietary diversity, is around 72%.

Crickets (Gryllus bimaculatus) are interesting as food because they are rich in protein (58-78%) and trace minerals (FAO 2013; Adul Razak et al 2012; Finke et al 2002; Barker et al 1998; Nakagaki et al 1987). Crickets common edible insects in Asia and a good source of income (Viwatpanich and Yhoung-aree 2005). Crickets have a much shorter life cycle compared with traditional livestock (pigs and cattle) (Gahukar 2011) and low emissions of greenhouse gases and ammonia (Poma et al 2017).

Capturing wild crickets could be a potential threat to their survival. Therefore, rearing crickets is an obvious way to ensure satisfying market demand year round. Crickets can eat a wide range of food sources such as weeds and agricultural and food industry by-products (Miech et al 2016). However, little information is available to date about cricket farming in Vietnam.

The aim of this research was to evaluate fresh biomass yield and growth of crickets (Gryllus bimaculatus) fed cassava leaves, water spinach and Coccinia grandis L as supplements to chicken feed. The hypothesis was that cassava leaves have potential to be used as cricket feed.

Materials and methods

Location and source of crickets

The study was conducted on a private farm located in Long Xuyen city, An Giang province, Vietnam. The crickets (n =7200; age 7 days) were sourced from a rearing unit in An Giang University.

Experimental design

The crickets were fed a basal diet normally given to growing chickens and three experimental diets in which the basal diet was supplemented with free access to leaves from sweet cassava, water spinach or Coccinia grandis L. The allocation to treatments was according to a Completely Randomized Design with 6 replications (each treatment/replicate had 300 crickets). The experiment lasted for 28 days.

Feeds, animals and management

Chicken feed was bought from the local market. According to the manufacturer, it contained 21.5% crude protein (CP), 7% crude fiber (CF) and 87% dry matter (DM). Chicken feed was offered ad libitum on plastic plates. Cassava leaves, water spinach and Coccinia grandis L. were harvested in the fields around Long Xuyen city and also offered ad libitum, but laid in the bottom of cages. The crickets were offered feed in the morning.

Seven thousand, two hundred crickets (Gryllus bimaculatus) at 7 days old were sourced from a rearing unit in An Giang University. They were housed in groups of 300 in plastic mesh cages (50x30x20 cm) in which conventional cardboard egg holders (width 30cm, length 50 cm, height 10 cm) were placed to provide hiding and moulting places for the crickets. The crickets in each cage were weighed together at the start of the experiment and then after 14 and 28 days, before feeding in the morning, using an electronic scale. The amounts of feed offered and refused were recorded. Feed conversion ratio (FCR) was calculated by dividing the total feed DM consumption by the total weight gain.


Photo 1. Coccinia grandis L.	Photo 2. The cages housing the crickets

Chemical analysis

Samples of feeds offered and refused were analysed for DM, CP and ash according to AOAC (1990).

Statistical analysis

The data from the experiment were subjected to analysis of variance using the General Linear Model (GLM) procedure of Minitab Software Release version 17 (2013). Sources of variation were treatments and error.

Results and Discussion

All the leaves were richer in crude protein and crude fiber than the chicken feed (Table 1).

Table 1. Mean values for chemical composition of the feeds, %
Item	DM, %	% of DM
Item	DM, %	CP	CF	EE	OM

Chicken feed	87.7	22.2	2.48	3.87	92.9
Coccinia grandis L.	12.4	26.2	12.5	5.19	78.0
Cassava	27.2	31.4	12.8	7.02	94.6
Water spinach	15.4	27.0	8.59	3.69	88.5

The intake of leaves was higher when these were sourced from cassava compared with water spinach or Coccinia (Table 2). Supplementation with all sources of leaves led to increases in the daily intake of crude protein and crude fiber.

Table 2. Feed intake during the experiment
Treatment	DM intake, mg/cricket/d			Intake, mg/cricket/d
Treatment	Chicken feed	Leaves	Total	CP	CF	EE	OM

Chicken feed	46.5^ab	0^c	46.5^b	10.8^b	1.12^c	2.03^c	96.3^a
Cassava leaves	42.2^b	7.24^a	49.5^ab	12.2^a	1.78^a	2.51^a	96.3^a
Coccinia grandis L.	48.0^a	4.44^b	52.4^a	12.3^a	1.65^a	2.35^ab	95.2^c
Water spinach	47.7^a	4.01^b	51.7^ab	12.2^a	1.47^b	2.26^b	95.7^b
SEM	1.33	0.131	1.37	0.296	0.041	0.051	0.097
p	0.022	<0.01	0.026	<0.01	<0.01	<0.01	<0.01
^abc Means within columns with different superscripts are different at P<0.05

Table 3. Mean values for increase in total biomass, daily weight gain and feed conversion of crickets fed chicken feed alone or supplemented with fresh leaves of cassava, water spinach or Coccinia for 28 days
Treatment	Gain in biomass, g	Initial weight, mg/cricket	Final weight, mg/cricket	ADG, mg/ cricket/d	FCR

Chicken feed	228^b	11.5	1015	35.0^b	1.33^ab
Cassava leaves	262^a	11.4	1063	39.0^a	1.27^b
Coccinia grandis L.	237^b	11.1	1071	37.9^ab	1.39^ab
Water spinach	221^b	11.3	1059	36.5^ab	1.42^a
SEM	5.61	0.29	28.4	0.91	0.08
p	<0.01	0.85	0.51	0.031	0.049
^ab Means within columns with different superscripts are different at p<0.05

The total biomass of the crickets was increased by 14% when they had access to fresh cassava leaves as well as commercial chicken feed (Table 3). There were no benefits in biomass growth when the chicken feed was supplemented with leaves from water spinach or Coccinia grandis.

Figure 1. Effect on growth rate of crickets having access to fresh leaves as well as chicken feed

Conclusions

Over a period of 28 days, the total biomass yield of crickets was increased by 14% when they had free access to fresh cassava leaves as well as commercial chicken feed.
When leaves from water spinach and Coccinia grandis were offered as supplements they were consumed in smaller quantities, as compared with cassava leaves, and there were no benefits in biomass growth of the crickets compared with access to chicken feed alone.

Acknowledgements

The authors are grateful for the financial for this research from An Giang University, Vietnam National University-Ho Chi Minh. The authors would also like to thank the Department of Animal Husbandry and Veterinary, Faculty of Agriculture and Natural Resources of An Giang University for infrastructure support.

References

Abdul Razak I, Ahmad Y H and Ahmed E A E 2012 Nutritional evaluation of house cricket (Brachytrupes portentosus) meal for poultry. 7th Proceedings of the Seminar in Veterinary Sciences, 27 February – 02 March 2012. Available at: http://psasir.upm.edu.my/26769/1/PROCEEDING%204.pdf

AOAC 1990 Official Methods of Analysis, 15th edition. Association of the Official Analytical Chemists. Washington D.C.

Barker D, Fitzpatrick M P and Dierenfeld E S 1998 Nutrient composition of selected whole invertebrates. Zoo Biology, 17 (2): 123-134

Chaparro Camila, Oot Lesley and Sethuraman Kavita 2014 Overview of the Nutrition Situation in Seven Countries in Southeast Asia. Food and Nutrition Technical Assistance III Project (FANTA) 1825 Connecticut Avenue, NW Washington, DC 20009.

Finke M D, Sunde M L and DeFoliart G R 1985 An evaluation of the protein quality of Mormon crickets (Anabrus simplex Haldeman) when used as a high-protein feedstuff for poultry. Poultry Science 64, 708-712.

Food and Agriculture Organization (FAO) 2013 Cricket Farming for Human Consumption. Available at: http://teca.fao.org/read/7927

Gahukar R 2011 Entomophagy and human food security. International Journal of Tropical Insect Science, 31, 129-144.

Miech P, Berggren Å, Lindberg J E, Chhay T, Khieu B and Jansson A 2016 Growth and survival of reared Cambodian field crickets ( Teleogryllus testaceus) fed weeds, agricultural and food industry by-products. Journal of Insects as Food and Feed, 2, 285-292.

Nakagaki B J, Sunde M L and DeFoliart G R 1987 Protein quality of the house cricket, Acheta domesticus when fed to broiler chicks. Poultry Science Journal 66: 1367-1371.

Poma G, Cuykx M, Amato E, Calaprice C, Focant J F and Covaci A 2017 Evaluation of hazardous chemicals in edible insects and insect-based food intended for human consumption. Food and Chemical Toxicology, 100, 70–79.

UNICEF 2012 Nutrition Glossary: A Resource for Communicators. Available from: http://www.unicef.org/lac/Nutrition_Glossary_(3).pdf.

Viwatpanich K and Yhoung-aree J 2005 Edible Insects in the Laos PDR, Myanmar, Thailand, and Vietnam. Ecological implications of minilivestock. New Hampshire: Science Publishers, 415-440.

Received 16 December 2019; Accepted 3 January 2020; Published 1 February 2020

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