Comparative Study of Biological Characters of Silkworm Eggs

Comparative Study of Biological Characters of Silkworm Eggs

1) 2) 2) 2) 1) Ioan PAŞCA , Emilia1) M. FURDUI* ,1) Liviu Al. MĂRGHITAŞ1) , Daniel DEZMIREAN , Dana PUSTA , Adrian CÎMPEAN , Mihai BORZAN , Adrian MACRI 1) Department II-Animal production and Food safety, Faculty of Veterinary Medicine, University2) of Agriculture Sciences and Veterinary Medicine, Cluj-Napoca, Romania Department II-Technological Sciences,[email protected] Faculty of Animal Science and Biotechnologies, University of Agriculture Sciences and Veterinary Medicine, Cluj-Napoca, Romania *Corresponding author, email:

DOI:10.15835/buasvmcn-asb:10812Bulletin UASVM Animal Science and Biotechnologies 72(1) / 2015 Print ISSN 1843-5262; Electronic ISSN 1843-536X

Abstract Bombyx mori L. et al., et al.,The silkworm et al., is a domesticatedet al., insect considered etas aal., reference in severalet al., domains (Mauchampet al., 2008). The theoretical and practical importance of the silkworms are shown in many studies (Nagaraju 1996; Kipriotis 2000; Sudhakara 2003; Vassileva 2004; Petkov 1998; Matei 2002; 2005). This study was conducted to compare four monovoltine breeds of Romanian silkworm, hatching in specificBombyx conditions, mori in different years (2001 and 2008), to see if there is a major difference between the biological characters of eggs belonging to those breeds in time. For both 2001 and 2008 years, four breeds AC29, AC, B1 and AB of (eggs) were obtained from SC SERICAROM (Bucharest, Romania) and the same microclimate conditions were assuring. In total, per data set of each year were 16 variants because each of the breed was hatch in four variants, for more complete results of analyzed samples. The evaluation was made on the base of indices used for classified biological characters of silkworm eggs, comparative data shows that, between the same breeds hatching in different years, there is no significant difference. According to biological characteristics, the study allowed us to make a classification of the analyzed breeds. In the present research, we demonstrated that biological characters of silkworm eggs were well preserved and there are no significant variations between both set of data takenKeywords: in study. biological character, Bombyx mori, breeds, monovoltine, silkworm

INTRODUCTION Bombyx mori L. is a reserve of biodiversity and a source of alleles that Mulberry silkworm can be easily retrieved for the genetic enhancement well-known lepidopteran with a long history of popular strains. especially for commercial extraction of the silk in The growth and development of silkworm is conditionssericiculture and industry the domestication and has lost process. some features greatly influenced by environmental conditions through many years of breeding under artificial such as biotic and abiotic factors. Among the abiotic factors, temperature plays a major role Unfortunately silkworms are no longer on growth and productivity of silkworms, as observed in nature and are totally dependent on silkworms are cold-blooded animals, temperature human intervention for their survival. Genetic will have a direct effect on various physiological stocks of this species are found only in germplasm activities (Rahmathulla, 2012). Another abiotic banks. Silkworm germplasm banks are important factor is represented by humidity which interacts 50 et al

PAŞCA with the availability of free water and with the Regarding the silkworms, eggs incubation water content of the food and it mostly shows was realized using the gradual raising of the indirect effect on growth and development. temperature. This method is used especially Those abiotic factors play an important role for incubating eggs kept in the refrigerator and on the consumption and utilization of food. Also proceed as follows: after removing the eggs from in literature it is well known that the majority the fridge, they stay three days at +15°C, two0 of the economically important genetic traits of days at +18°C and 20°C, four 23º days at +18 C silkworms are qualitative in nature and that and +24° C, and the balance between +25°C and phenotypic expression is greatly influenced by +26°C. Gradual increase in temperature is best, etenvironmental al., factors et such al., as temperature,et because it corresponds to physiological processes al.,relative humidity, light, and nutrition (Chatterjee during incubation. In room in which incubation of 1993, ThiagarajanBombyx mori L., 1993; Ramesha silkworm eggs was performed was set a thermo- 2009). hygrometer which served to monitor incubation In present comprises a large regime like temperature and humidity. number of breeds and synthetic inbreed line, Light used during the incubation was natural, which represent high( degree of et divergence al., with but supplemented with artificial until the eggs respect to geographical origins and quantitative bleaching, after which they were provided 36 hours and qualitative traits Srivastava 2005). dark and then went back to lighting regime. This The aim of this study is to compare four method was used to obtain a higher percentage of monovoltine breeds of Romanian silkworm, hatch grouped hatching, this increase depending on the in separated years (2001 and 2008), to see if there further experiments. In total per data set of each is a major differences of biological characters of year were 16 variants because each of the breed eggsMATERIALS of those breeds AND in time. METHODS was hatch in four variants, for more complete results of analyzed samples. Biological indices of the eggs (number of eggs/hatching and hatching Silkworm eggs were obtained from SC. percents results are expressed as the average of Sericarom SA from Bucharest, Romania who four different pontes within the same breed. represents bank germplasm, after that eggs was Our research was focus on follow characters: put for hatching at University of Agricultural color of eggs, number of eggs, hatching percent, Sciences and Veterinary Medicine Cluj-Napoca.. and RESULTSnumber of ANDdays ofDISCUSSION interval for hatching. The biological material was represent by four monovoltine breeds AC29, AC, B1 and AB For both 2001 and 2008 years, the same microclimate The evaluation of qualitative traits helps as to conditions were assured, such as temperature, characterize and differentiate between different relative humidity, light. strains from SC Sericarom SA. Bucharest, Romania. Experimental hatching of silkworm were In addition to help to maintaining the germplasm conducted in May for both 2001 and 2008 years, using bank, these analyses are crucial in choosing the specific inventory. Before beginning the research parents involved in the productionB. mori of superior experimental laboratory and entire inventory for hybrids in breeding programs. Moreover, theet this purpose, have been disinfected with Virkon. al.,biological performance of can reflect on Incubation is the period required to complete maximum final silk production potential (Porto the development of the embryo in the egg, for which 2004). purpose they are kept in optimal conditions of In this period optimum microclimate temperature, humidity, light and ventilation. Start of parameters were ensured in the hatching of eggs date for hatching series was established according of the silkworm, for a high percentage of hatching. to the evolution of mulberry vegetation,Bombyx somori that on Incubation period was influenced by of the day of hatching larvae, mulberry had 3-5 leaves. temperature, humidity and lightness. Eggs average As breeding material, eggs of , are days for B.hatching mori in the experiment were 13 days. named “seed” and the efforts of a single female is We analyzed several biological characteristics called “ponta.” of four strains two of Chinese and two Bulletin UASVM Animal Science and Biotechnologies 72(1) / 2015 Japanese origin, the breeds of Japanese origin 51

Comparative Study of Biological Characters of Silkworm Eggs

a) Egg color when layed by the b) spawning color after 3 days from laying female butterfly. (original).

Fig. 1. Comparative results, year 2001 vs. 2008 of total Fig. 2. Comparative results, year 2001 vs. 2008 of number of eggs/ hatching. number of hatching eggs.

has dark metallic gray and elliptical-shaped eggs (AB, B1); and those of Chinese origin (AC, AC29) has gray-green and oval-shaped eggs. The color of chorion is white to Japanese breed and yellow to those of Chinese breed. Both color of embryo and the egg chorion represent characters used for selection ofTable silkworms. 1

From , the average of Romanian breeds 597±45.5 eggs in terms of prolificacy and 90.46±42.05 of hatching percent % are above the mean (567±45.5) eggs that of other breeds used in industrial growth. Egg size, is a character of breed, with the Fig. 3. Comparative results, year 2001 vs. 2008 of longitudinal axis of 1.5 mm and 1 mm transverse hatching percent %. axis; these dimensions are correlated with the number of eggs in a gram (between 1300 to 2000 Bulletin UASVM Animal Science and Biotechnologies 72(1) / 2015 52 et al

PAŞCA Tab. 1. Bombyx mori Biological parameter of eggs. Average values of biological characters in , genetic germplasm, egg phase (Cristina Bojan, 2008). ± ± No. Breeds origin Prolificacy± Hatching percent± % 1. China 517.5± 24 90.15± 0.90 2. Japan 586± 24.5 88.86± 2.26 3. Romania 597 45.5 90.46 42.05 4. Average 567 31.33 89.82 15.07 Figure 1 eggs). Regarding of number of eggs/hatching from of eggs, number of eggs, hatching percent, and can be observed that is a slight decrease number of days between hatching), we didn’t of the total number of eggs deposited byFig. a female 2 found an significant difference between the two butterfly in year 2008 compared to 2001 year. differentREFERENCES years when the research was conducted. Regarding the number of hatching eggs ( ), for silkworms breed AC and AB in 2008 has a slight Bombyx mori L increase in the number of eggs hatched. 1. Benţea M (2006). Caracterizarea unor hibrizi de viermi Fig. 3 de matase ( .) crescuti in zona Transilvaniei, A very important character is the percentage teză de Doctorat, USAMV Cluj-Napoca. of hatching ( ), the lowest percentage of 2. Benţea M, L Al Mărghitas, D Dezmirean, AlexandraBombyx Matei, hatching was recordedet al. at breed AC 29 (93.05%), MoriI Szendrei L (2003). Research on the prolificity and the a higher value than that obtained for the same hatching of the breed and hybrid combination of breed by Benţea 2003 (90.71%), while the . Buletinul USAMV, 59, 284. maximum value for this characters has been found 3. Bojan Cristina (2008).Bombyx Cercetări mori privind factorii care influenţează dezvoltarea glandei sericigene la fluturele de at breed AC (96.62%). et al mătase al dudului , teză de doctorat USAMV The values obtained are comparable with Cluj-Napoca. those reported in literature Trag . (1992), 4. Chatterjee SN, Rao CGP, Chatterjee GK, Ashwath SK, which found for the parental breeds, a number of Bombyxand Patnaik mori AKL (1993). Correlation between yield and 520-630 eggs/hatching, otherset al. authors as Bentea biochemical parameters in the mulberry silkworm, (2006) obtained the following values: 505-660 , Theoretical and Applied Genetics, vol. 87, no. 3, 385–391. eggs/hatching,et al Vassileva (2004) reported a 5. KipriotisBombyx E,mori Petkov L.) N, Natcheva Y, Tzenov P, Grekov D total of 506-560 of number of eggs/hatching and (2000). Study on some Bulgarian silkworm hybrids Rao . (2003), 415-458 of eggs/hatching. The ( in conditions of Greece. Journal of study also allowed as performing a classification Animal Science (3), 65-68. of the analyzed breeds according to biological 6. Matei A, Marghitas L, Ciulu M, Pasca I, Dinita G (2002). characteristics, the best conserved over the time Hibrizi de viermi de matase de perspectiva pentru was one breed of Japanese origin (B1) and one of exploatatiile agricole mixte sericicole. Cea de a 31-a Sesiune de Comunicari Stiintifice a Facultatii de Zootehnie ChineseCONCLUSION origin (AC). Bucuresti–USAMV. 7. Matei A, PetkovBombyx N, mori Dezmirean sp D, Petkov Z, Vasileva Y, Ciulu M (2005). Comparative study of the perspective silkworm In this study, we demonstrated that biological hybrids . From Romania and Bulgaria characters of silkworm eggs were well preserved destined to sericultural familial associations. Buletinul USAMV Cluj-Napoca, 61/396. in time and we didn’t find any significant Bombyx mori 8. Mauchamp B, Royer C, Chavancy G (2008). The silkworm variations between both set of data taken in study. an insect in continuous metamorphosis- In the number of eggs/hatching we found a slight Seristech- Proceeding of the first international conference decrease in the total number of eggs deposited “sericiculture-from tradition to modern biotechnology”, by a female butterfly in 2008 compared to the AcademicPresCluj-Napoca, 15. Bombyx mori year 2001. The breeds AC and AB in 2008 had a 9. Nagaraju J, Raje Urs, Datta RK (1996). Cross breeding slight increase in the number of hatched eggs and heterosis in the silkworm, , A review. Sericologia 36, 1-20. compared with 2001. The percentage of hatching 10. Petkov N and Natcheva Y (1998). Study on regularity of was comparable with the data found in literature. the inheritance of the viability and productivity characters In our research, in the characters evaluated (color Bulletin UASVM Animal Science and Biotechnologies 72(1) / 2015 53

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