Production Performance of Eri Silkworm ( Samia cynthia ricini ) with Cassava Leaves Feed ( Manihot utilissima ) on Different Mountages Media

Eri silkworm ( Samia cynthia ricini ) is a potential silk producing insect in Indonesia. This study aimed to analyze the production performance of the S. c. ricini silkworm with cassava leaves feed ( Manihot utilissima ) and their cocoon productivity that mounting on different mountages (wood and carton), and also calculate the financial analysis. The silkworm was reared in altitude 176 m asl. Production performance observed were feed consumption (ingesta and digesta), larval productivity (length, breadth, and weight), and cocoon productivity (the effective rate of rearing and cocoon quality). Feed consumption and larval production were analyzed descriptively, the effective rate of rearing was compared using a t-test, cocoon quality was analyzed using a completely randomized design factorial 2 × 2 pattern. The first factor was sex and the second factor was mountages media that were used with three replications. Financial analysis was calculated using profit, R/C ratio, and BEP. The results showed the optimum consumption of cassava leaves during the study was 27.17 ± 2.39 g of feed ingestion and 19.15 ± 2.30 g of feed digestion. Mountages media did not significantly (P>0.05) influence the effective rate of rearing and cocoon quality. Cocoon weight, pupal weight, and shell ratio was affected by cocoon sex. Financial analysis calculation result showed that wood mountages gives the best value, with the profit value was Rp 21.877.819/year, R/C ratio was 1.61, BEP of yarn was 5.67 kg, BEP of eggs was 110.10 box.


INTRODUCTION
The raw materials of the eri silk industry were obtained entirely from Samia cynthia ricini cultivation which the majority is produced in India.Renuka and Shamita (2014) state that S. c. ricini is a type of polyvoltine silkworm that is capable of raising five to six crops in a year.Eri silkworm is also a polyphagous insect with the main host plants castor (Ricinus communis L.) and kesseru (Heteropanax fragans Seem.) and other important host plants such as payam (Evodia fraxinifolia Hook.), cassava (Monihot utilissima Phol.) and barpat (Ailanthus grandis Roxb.).
Feed is one of the factors that affect the productivity of S. c. ricini.Cassava (M.utilissima) is one of the potential host plants for S. c. ricini which is widely cultivated in Indonesia.The effective rate of rearing S. c. ricini with cassava leaves feed (87.85%) was below the primary hosts of castor (89.40%), and above the other host plants leaves: arduso (85.93%), indian almond (75.04%), and banyan (65.48%) (Birari et al. 2019).Larval productivity is also influenced by environmental conditions, low environmental temperatures will extend the larval cycle which causes the duration of feeding to be longer.This will affect in increase larval and cocoon productivity (Subramanian et al. 2013).Indonesia has a diverse topography that will affect environmental conditions.The study was conducted in a lowland area (176 m asl) which is prone to high temperatures and low humidity.A study of the productivity of eri silkworms with cassava leaves in the lowlands is needed to add the data collection regarding the potential for S. c. ricini development in Indonesia.This is because generally silkworms are kept in the highlands with cool air.
The economic value of silkworm rearing can be known from cocoon productivity.Atmosoedarjo et al. (2000) stated that cocoon productivity was influenced by mature larval handling, cocoon handling when harvested, and the mountages media that were used.Various mountages were used by S. c. ricini cultivators.The most mountages commonly used in Indonesia were dried banana leaves, cartons, and woods.This may influence the cocoon productivity and economic traits.Wood and carton mountages were used in this study to determine the efficient mountages for S. c. ricini based on productivity and economic.This study aimed to analyze the production performance of the S. c. ricini silkworm that reared with cassava leaves fed (M.utilissima) and their cocoon productivity that mounting on different mountages (wood and carton) and calculate the financial analysis.

Material
This research was conducted at The Silk Laboratory, Departement of Animal Production and Technology, Faculty of Animal Science, IPB University for 5 months.The altitude of the research location is 176 m asl.The materials used were 360 S. c. ricini larval.S. c. ricini seed were derivatives from Jantra Mas Sejahtera Farm, Yogyakarta which had been maintained for a generation at the Silk Laboratory.Other materials used were cassava (M.utilissima) leaves and 2% formalin solution to disinfect the eggs.

Eggs collection and incubation
Cocoon seeds were cleaned from floss fibers and placed in the mating place.The moth that had to emerge and copulate was transferred to a new mating place at 08.00 am.After copulating for four hours, female and male moths were separated and female moths were oviposited for 20 hours.Eggs were collected and disinfected using a 2% formalin solution for five minutes then the eggs were washed under cleaning water until clean.Eggs were divided into trays and incubated until hatching.

Larval rearing
The eri silkworm larvae were fed three times during the young ages (1 st -3 rd instar) and four times during the late ages (4 th -5 th instar).Young ages larva was given sliced cassava leaves while late ages larva was fed with cassava leaves without being sliced.The content of cassava leaves given as feed is presented in Table 1.The second and third instar were reared with a density of 0.10 larva cm -2 and expanded to 0.05 larva cm -2 when entering late ages larval.Data collection began on the second instar to avoid high mortality because the first instar was very susceptible to touch and pressure.Data collected were temperature, humidity, feed consumption (ingesta and digesta), feed consumption efficiency, and larval productivity (length, breadth, and weight of larvae).The consumption of ingesta is the weight of the leaves consumed by the larvae, while the consumption of digesta is the weight of the leaves consumed by the larvae minus the weight of the faeces.Feed consumption efficiency is the percentage increase in larval weight divided by the amount of feed consumed by the larvae.

Mounting
At the late stage fifth instar, larval that release wet fecal matter, the body became shorter and translucent, and crawl on the rearing area seeking a place to spin cocoons was transferred into mountages media.Larval was divided into two different mountages media (wood and carton).Cocoon harvested on the sixth day after being transferred into mountages for data collection.The data observed were the effective rate of rearing and cocoon quality.The effective rate of rearing was the percentage of cocoons produced divided by the initial number of larvae kept, while observations of cocoon quality consisted of cocoon weight, pupa weight, floss weight, single shell weight, and shell ratio.

Financial Analysis
Financial analysis was calculated based on profit, revenue cost ratio (R/C ratio), and break-event point (BEP).The feed consumption, cocoon production, and egg production from both mountages was calculated based on the result of the study.Investment costs consist of rearing racks, trays, mountages, and rearing equipment, while the total cost consist of employee payment, building fees, and depreciation expenses.

Data Analysis
The effective rate of rearing between wood and carton mountages was analyzed by t-test.The confidence interval used was 95%.The mathematical model used was as follows (Montgomery 2013): The data were analyzed with analysis of variance (ANOVA) and if there were differences between treatments, it was continued with the Tuckey test.

Temperature and Humidity
Rearing room temperature and humidity results are presented in Table 2. Temperature and humidity had a significant affect on animal behavior, productive and reproductive performance, and distribution of insects.According to Hailu et al. (2018) the optimum rearing temperature for young ages larval (1 st -3 rd instar) is in the range of 26-28 ℃, while late ages larval (4th-5th instar) is in the range of 24-26 ℃.The results showed that the rearing temperature of young ages larval was in the range of optimum range temperature, but the rearing temperature of late ages larval was in the range of optimum rearing temperature range.Teronpi et al. (2020) stated that rearing temperature will affect the physiological condition of silkworms in nutrient absorption, digestion, transportation, and circulation systems.It affected larval duration and survivability.Hailu et al. (2018) stated that the optimum humidity for young ages larvae is in the range of 85-90%, while the optimum humidity for late ages larvae is 70-80%.The humidity of the young ages larval during the observation was below the optimum humidity, while the humidity of the late ages larval exceeded the maximum optimum humidity limit.The humidity conditions of the rearing room fluctuated because of frequent rain during the observation.The humidity of the rearing room will play a role in the regulation of the body temperature which indirectly affects the growth and physiological condition of larval (Teronpi et al. 2020).The rearing site was in the lowlands (below 250 m asl), so it was sensitive to high temperatures and low humidity.Ventilation of the rearing room was opened when the room humidity was high and ventilation was reduced and placing trays of water when the room humidity was low.

Feed Consumption and Feed Consumption Efficiency
The quality and quantity of leaves given to silkworms affected the animal productivity.The results of feed consumption are presented in Table 3. Feed consumption results were higher than the observations of Gururaj et al. (2017) using Bangalore local variety castor leaves with total feed ingestion of 26.25 g and total feed digestion of 17.11 g.Nursita (2008) stated that the consumption of silkworms is  increasing as the moisture content of leaves.Cassava leaves moisture content (84.59%) was higher than castor leaves (80.49%) (Deuri et al. 2017).
Feed conversion efficiency resulted in this study (Table 4) were lower than Gururaj et al. (2017) on instar III, IV, and V respectively were 18.02, 28.78, and 19.25 for efficiency of conversion of ingested feed, also 33.83, 68.45, and 33.98 for efficiency of conversion of digested feed.The presence of antinutrient components such as tannin and crude fiber can reduce feed digestibility (Shifa et al. 2014).Deuri et al. (2017) reported that tannins and crude fibers content in castor leaves was 1.46% and 5.53%, very different from the feed content given during the research.Lower feed conversion efficiency in this study was a result of the presence of high crude fiber content of cassava leaves.In addition, the temperature and humidity of the rearing room were not at optimum conditions, which also affects the feed conversion efficiency.The feed consumed was not only used for larval growth but also used for adjusting body conditions to the environment.This leads to the low feed conversion efficiency.

Larval Productivity
Larval productivity was observed including the larval length, breadth, and weight.The length, breadth, and weight of the larval were measured at the end of the instar before larval molting.Larval productivity results (Table 5) were still lower than larvae with castor leaves feed that reaches maximum larval length (58.45±1.19mm), larval breadth (11.93±0.36mm) (Birari et al. 2019), and larval weight (7.65 g) (Birari et al. 2019).This may be due feed conversion efficiency rate of cassava leaves being lower than castor leaves.In addition, rapid changes in environmental conditions due to frequent rain events during the study might had an effect on the decrease in larval productivity.

Cocoon Productivity
Cocoon is a silkworm product that has economic value due it is the raw material for silk fibers and biomaterials.Wood and carton mountages did not affect the effective rate of rearing (Table 6).Ibrahim et al. (2015) stated that mountages could affect the cocoon productivity.
Based on the results, wood and carton mountages were good as alternative mountages for S. c. ricini.Birari et al. (2019) reported that the effective rate of rearing using castor leaves and cassava leaves was 89.40% and 87.85% respectively, Kumar and Elangovan (2010) reported that the effective rate of rearing using castor leaves and cassava leaves was 91.05% and 88.00% respectively.The average yield of cocoon production during the study was still lower than the two studies, this is possible due to the influence of environmental conditions and feed conversion effectivity that affects larval survivability.
The mountages used had no significant difference in affected single cocoon weight and pupal weight (Table 6).Single cocoon weight and pupal weight in this study were still lower than Shifa et al. (2014) study by using local variety castor leaves with an average single cocoon weights and pupal weights of 3.14 g and 2.70 g respectively.This reflects that feed consumption efficiency plays important role in single cocoon weight and pupal weight.The high feed consumption efficiency of castor leaves will increase the weight of the final instar larval which affects the increase of single cocoon weight and pupal weight.The single cocoon weight and the pupal weight showed significantly different results (P<0.05) in different sex (Table 6).Female cocoons were heavier than male cocoons, these results are similar to Endrawati and Fuah (2012) results on the Attacus atlas cocoons.Bu et al. (2022) stated that female cocoons stored of biomass material to lay eggs so that female cocoons were heavier than male cocoons.
The floss weight and single shell weight during the study were not influenced by the mountages or by sex (Table 6).Estetika and Endrawati (2018) reported floss weight was affected by the mountages.The results showed that the wood and carton mountages had the same good quality based on floss production.The smaller amount of floss was better because the part that was wasted for floss is used to form the cocoon shell (Baskoro et al. 2011).Normally, multivoltine races have a greater number of floss than bivoltine and univoltine races (Sahana et al. 2019).The average floss weight during the observation was much greater (0.09 g) than the floss weight from Bombyx mori in observations by Estetika and Endrawati (2018) which was at an average of 0.015 g.Rajkhowa et al. (2015) revealed that characteristics of the S. c. ricini cocoon contain more floss than other types of silkworm cocoons.The single shell weight of the cocoon from the study was (0.14 g) still lower than Shifa et al. (2014) which was at an average of 0.44 g.This is because the single cocoon weight used on this study was relatively low which was supported by Subramanian et al. (2013) that there was a positive correlation between single cocoon weight and single shell weight of the cocoon.Shell ratio showed significantly different results (P<0.05) in different sex (Table 6).This may due to the feed consumed by females is not only used for cocoon formation but also for egg formation which makes female cocoon shells ratio smaller than males.Shell ratio produced was smaller than Shifa et al. (2014) which was around 14.07%.This is due to the single cocoon weight produced during the study being lower.Subramanian et al. (2013) stated that there is a positive correlation between single shell weight and shell ratio.
Financial Analysis Based on the calculation results, the lowest investment costs were obtained from carton mountages this is due to the price of the raw material for making carton mountages being cheaper than wood mountages.Although the price was cheap, the carton mountages had lower durability than wood, so it needs to be replaced once a year.This makes total cost of carton mountages become high.Financial analysis based on its components is presented in Table 7.
The highest revenue and profits were obtained from wood mountages, this result as same as Mutiara and NH (2017) with a profit of Rp 1.812.750/month(Rp 21.753.000/year).Highest result of wood mountages due more controlled mounting process, where one larval was mounted at one mounting place.Carton mountages were very susceptible to inaccurate mounting time.The larval moved too early causing the mountages easily damaged due to the last wet fecal matter of excreta.Larval that have not entered mounting time also tend to die due to lack of feed and energy.Dead larvae will make the cocoons that have been formed dirty.The production of yarn and eggs is still above the BEP value and the R/C ratio is above 1, so S. c. ricini rearing is still in profitable position.

CONCLUSION
Maximum larval performance of S. c. ricini that reared using cassava feed (M.utilissima) under temperature range 26-28 ℃ and humidity 72-83% were larval length (59.65 ± 4.36 mm), larval breadth (9.80 ± 0.77 mm), and larval weight (4.18 ± 0.60 g).The wood and carton mountages did not affect the cocoon productivity.Female cocoon weight and pupal weight were heavier than males cocoon weight and pupal weight, while females shell ratio was lower than males.Wood mountages give the best value of financial analysis with profit value was Rp 21.887.819/year, R/C ratio was 1.61, BEP of yarn was 5.67 kg, BEP of eggs was 110.10 box.
of wood mountages sample; n2 = the number of carton mountafes sample.Cocoon quality was analyzed using a completely randomized design factorial 2×2.The first factor was cocoon sex and the second factor was different mountages (wood and carton).Each treatment was repeated three times with the following mathematical model (Walpole et al. 2012): Yijk = observed value of i mountages media and j cocoon sex in k replication; µ = general mean; αi = the effect of i mountages media; βj = the effect of j cocoon sex;( α β ) ij = the effect of interaction i mountages media with j cocoon sex; εijk = treatment error of i mountages media and j cocoon sex in k replicate.

Table 2 .
Temperature and humidity of rearing room

Table 7 .
Financial analysis of Samia cynthia ricini rearing