The Changes of Nutrient Content of Cassava Peel (Manihot esculenta Crantz) That Fermented by Indigenous Microorganisms (IMO) For Animal Feed

Cassava peel is the waste of processing cassava which is promising enough to be used as alternative animal feed. However, cassava peel has a fairly low nutrient content. Fermentation was one of the way to increase the quality of cassava peel. Fermentation used in this research utilized Indigenous Microorganisms (IMO) with the main substance was the cassava peel itself. This research lasted for 3 months started from December 2018 to February 2019 at the Laboratory of Microbiology and Laboratory of Feed Processing Science and Technology Department of Animal Science Faculty of Agriculture University of Sumatera Utara and Laboratory of Agrichemists and Natural Resources at the Industrial Research and Standardization Office of Medan. This research was designed using Completely Randomized Design (CRD) factorial pattern of 3 x 3 with 3 replications, as factor I was the dose of Indigenous Microorganisms (IMO) and factor II was the duration of fermentation. The parameters measured were water content/dry matter, crude fat, crude protein, crude fibre, ash, and Non Nitrogen Free Extract (NNFE) using proximate analysis. The results showed that fermentation of cassava peel using Indigenous Microorganisms (IMO) with the variation of Indigenous Microorganisms (IMO) dose and duration of fermentation give effects, that were increased water content, crude protein, and Non Nitrogen Free Extract (NNFE) and decreased dry ingredient, crude fat, crude fibre, and ash content.

Various types of processing were carried out on feedstuffs in order to increase the nutrient content and reduce antinutrient substances, one of that was fermentation. Fermentation is the process of breaking down organic compounds into simpler compounds involving the role of microorganisms [3].

Methods
The research used Completely Randomized Design (CRD) factorial pattern with 2 factors, each factor consisting of 3 levels (3 x 3) with 3 replications, so that 27 research units were obtained.  dose of IMO (D) L 1 (3 days) L 2 (5 days) L 3 (7 days)

Parameters of Research
The parameters of the research were moisture content, dry matter content, crude fat content, crude protein content, crude fiber content, ash content, NNFE content, and cyanide acid level.

Moisture Content
Moisture content = sample weight before drying x 100%

Ash Content
Ash content = (sample weight + dish after furnace) -empty dish weight x 100% sample before furnace weight

Conduction of Research
The research was conducted in two steps, they were the making of Indigenous Microorganisms (IMO) and fermentation of cassava peel.

Analysis of Data
Data obtained and analyzed by Completely Randomized Design (CRD) factorial pattern, if obtained real or very real results then continued with Duncan's mean range test (DMRT). From the results of the research was found that the higher dose of IMO and the longer the duration of fermentation caused an increased in moisture content. This was presumably because microbes carry out the process of metabolism of carbohydrate from cassava peel during fermentation to be used as an energy source and water was a by-product of this process. This was supported by the results of the research [4]. Notation with uppercase letter indicates the dose of IMO, notation with lowercase letter indicates the duration of fermentation.

Dry Matter Content
Based on the results of Duncan's mean range test (DMRT) was known that the interaction between the two factors decreased the dry matter content. The highest decreased of dry matter content was D 3 L 3 from 94,00 % to 88,67 % or decreased in the amount of 5,67 % and the lowest decreased in dry matter content in D 1 L 1 from 94,00 % to 93,09 % or decreased in the amount of 0,97 %. However, the D 2 L 2 treatment was found to be not significantly different from D 3 L 3 , because there was a decreased of dry matter content in fermented cassava peel, from 94,00 % to 90,46 % or decreased in the amount of 3,77 %.
The increased of water content was inversely proportional to the decreased in the dry matter content of fermented cassava peel. It was known that the higher dose of IMO and the longer fermentation duration would increased the moisture content of fermented cassava peel, so the dry matter content will be lower. This was according to research [5] whom found that after fermentation, dry matter content became lower. Information: The different superscripts on the same row and column show very significant differences (P < 0,01).

Crude Fat
Notation with uppercase letter indicates the dose of IMO, notation with lowercase letter indicates the duration of fermentation.
Based on the results of Duncan's mean range test (DMRT) was found that the interaction between the two factors resulted the highest decreased of crude fat content was in D 2 L 3 from 1,43 % to 1,04 % or decreased in the amount of 27,27 % and the lowest decreased of crude fat content was in D 1 L 1 and D 1 L 2 from 1,43 % to 1,16 % or decreased in the amount of 18,88 %.
However, the treatment of D 2 L 2 was known to be optimal treatment in reducing crude fat content in fermented cassava peel because the value was not significantly different from D 2 L 3 , which was from 1,43 % to 1,07 % or decreased in the amount of 25,17 %.
The decreased in crude fat content of cassava peel substrate was thought to be due to microbes produced lipase enzymes which function to degrade fat. The higher used of dose of IMO and the longer duration of the fermentation will increase the mass of microbes that worked to ferment cassava peel. Increased microbial mass, lipase enzymes produced would be higher. This was in accordance with statement [4]. Information: The different superscripts on the same row and column show very significant differences (P < 0,01).

Crude Protein
Notation with uppercase letter indicates the dose of IMO, notation with lowercase letter indicates the duration of fermentation.
Based on the results of Duncan's mean range test (DMRT) was found that the interaction between the two factors resulted the highest increased of crude protein content was in D 3 L 1 from 4,17 % to 5,77 % or increased in the amount of 27,73 % and the lowest increased of crude protein content occurred in D 1 L 3 from 4,17 % to 4,93 % or increased in the amount of 15,42 %.
However, the treatment of D 2 L 1 was known to be optimal treatment to increased crude protein content because the value was not significantly different from D 3 L 1 , which increased the crude protein content from 4,17 % to 5,60 % or increased in the amount of 25,54 %.
From the results of the research also was found that the higher dose of IMO given as fermentation starter of cassava peel, caused an increased of crude protein content. The higher dose of IMO that used in the fermentation caused the mass of microbes that worked on cassava peel fermentation would be increased. Microbes were living organisms where the body's constituent structure was protein, so it can be said that microbes were producers of Single Cell Proteins (SCP). The higher number of microbes that lived on fermented cassava peel, it would be increased the Single Cell Protein (SCP). This was in accordance with statement [4].
In addition, the increased in crude protein content was suspected because microbes that worked in the fermentation process converted inorganic N in the form of urea found in IMO to organic N (protein). This was according to the statement [6]. Furthermore, the increased in the protein content of fermented cassava peel by indigenous microorganisms was suspected because indigenous microorganisms contained protelitic microbes which produced protease enzymes that overhaul the protein into polypeptides which then become simple peptides. This was in accordance with research by [7]. The end result of this reshuffle was free amino acids and when analyzed, amino acids are counted as proteins so that crude protein levels increased.
However, the longer fermentation duration did not have positive impact on increasing crude protein content. The highest crude protein content occurred in fermentation on the third day, decreased on the fifth and seventh day. It was suspected that the decreased in crude protein content was due to the fermentation process, microbes degraded proteins into volatile ammonia (NH 3 ) compounds. The longer the fermentation time, the more protein was converted to ammonia which then evaporated so that the crude protein content dropped. This is according to research by [8]. treatment was known to be optimal treatment for reducing crude fiber content because the value was not significantly different from D 3 L 3 , which was the decreased in crude fiber content from 16,88 % to 12, 64 % or decreased in the amount of 25,12 %.

Crude Fiber
From the results of the research, it was known that the higher the dose of IMO used as fermentation starter and the longer the fermentation duration would have a positive effect on the decreased in crude fiber content. This was presumably because in IMO there are cellulolytic microbes that produce cellulase enzymes, in which this enzymes were able to degraded cellulose molecules. Thus, the higher the IMO dose and the longer the duration of fermentation took place, the higher the microbial mass that lived on the substrate, the more cellulase enzymes produced. This was in accordance with research [4]. Information: The different superscripts on the different row and column show very significant differences (P < 0,01).

Ash Content
Notation with uppercase letter indicates the dose of IMO, notation with lowercase letter indicates the duration of fermentation.
From the results of the analysis of variance was shown that the IMO dose and fermentation duration had a very significant effect (P < 0,01) on changes in ash content in fermented cassava peel. However, there was no interaction between the two factors. Based on the results of Duncan's mean range test (DMRT), it was found that there was a decreased in ash content of fermented cassava peel. In terms of the dose of IMO used, the highest average decreased in ash content was in D 3 from 6,78 % to 4,69 % or decreased in the amount of 30,83 % and the lowest average decreased in ash content in D 1 from 6,78 % to 5,49 % or decreased in the amount of 19,03 %. However, the used of IMO dose on D 2 was known to be optimal treatment because the reducing value was not significantly different from D 3 , which was from 6,78 % to 4,85 % or decreased in the amount of 28,47 %. Meanwhile, when divined from the duration of fermentation, the highest average decreased of the ash content in L 3 from 6,78 % to 4,61 % or decreased in the amount of 32,01 % and the lowest average decreased in ash content in L 1 from 6,78 % to 5,66 % or decreased in the amount of 16,52 %. The L 2 treatment has been optimal treatment in reducing the ash content in fermented cassava peel because the average decreased was not significantly different from L 3 , which was from 6,78 % to 4,94 % or decreased in the amount of 27,14 %.
The decreased in ash content was caused by microbial activity that degraded cassava peel resulting the increased in organic matter. The higher the dose of IMO and the longer fermentation duration, the more of microbes mass that worked in the fermentation process increased. Thus microbial worked during the fermentation process was more optimal in degrading cassava peel so that more organic matter were degraded and the ash content decreased. This was in accordance with research by [9] and [10].
The decreased in ash content identified an increased in the content of organic matter substrate.
Organic materials contain nutritional substances that are quite important, namely protein, fat, and carbohydrates, and vitamins. Through the fermentation process, the ash content of cassava peel is expected to decrease. Based on the results of the research, it was known that the use of MOL doses with a level of 3 % and duration of fermentation was 5 days will increase NNFE content in cassava peel. This dose of IMO and duration of fermentation provided the opportunity for microbes to grow optimally on the substrate. Thus, the microbial mass act in the process of changing organic matter on cassava peel was increasing. As was known, the more organic matter was degraded in the fermentation process, the lower the ash content would be. The impact of this was an increased in NNFE content. This was supported by the results of the study by [11].

Conclusion
Based on the results of the research, it was found that from the three levels of Indigenous Microorganisms (IMO) used and from three levels of fermentation duration, the dose of MOL 3% (D 2 ) and 5-day fermentation (L 2 ) was optimal and efficient treatment for increased water content, crude protein, and Non Nitrogen Free Extract (NNFE) and can reduced crude fat, crude fiber, and ash content in cassava peel.