Improved Nutrient Contents of Durio Zibethinus Murr Peel Fermented with Pleurotus Ostreatus and Its Addition in PUFA- Concentrate

The objective of this research was to evaluate nutrient contents of Durio zibethinus Murr peel powder fermented with Pleurotus ostreatus and its addition in PUFA- concentrate. There were two experiments have been conducted. First, fermentation process with experimental design of completely randomized treatments, F2: 2 week fermentation, F4: 4 week fermentation, F6: 6 week fermentation, and F8: 8 week fermentation with 4 replications. Second, incorporate the F8 Durio into PUFA- concentrate. Variables evaluated were in first experiment were in vitro VFA, GE, NDF and ADF. In second experiment were nutrient contents and fatty acid profile. Results showed that Fermentation of Durio zibethinus Murr peel powder fermented with Pleurotus ostreatus for 4-6 weeks seems to improve NDF, ADF, and GE ; while, fermentation for 8 weeks and incorporated into PUFA-concentrate could improve crude protein, ether extract and NDF, and lower ADF. However, it decreased fatty acid profile of SCFA, MedCFA, LongCFA, MUFA, PUFA, unsaturated, saturated, P/S, and U/S.


INTRODUCTION
Availability of feed is always as a concern for livestock farming. Durian or Durio zibethinus Murr is one of harvested fruits that its byproduct could be utilized as one of feed ingredients for ruminants. Its potency in Indonesia is huge, while, in Bengkulu Province is around 5040.8 ton/year. Its waste of Durio peel is about 60-70% (Suhaidi, 2004), equals to 3276.52 ton/year or Durio peel powder or 491.5 ton/year or 1346.6 kg/day. This byproduct could be used as potential feed; however, it needs treatment, such as fermentation using white rod fungi (Pleurotus ostreatus). This fungi grows well in any high fiber waste product media (Sangadji et al., 2008). This white rod fungi that is able to degrade lignin binds much more extensively than others, as it produces extracellular lignolitic ezyme, such as laccases, lignin peroxidases and Mn peroxidases (Hatakka, 1994). This fungi also improved crude protein of fermented Durio in 0 to 8 weeks, from 4.31 to 5.69%, respectively; while crude fiber decreased as reported by Suciyanti et al. (2015). Hartono et al. (2015) reported that in vitro organic matter digestibility (IVOMD) is significantly decreased in 2 weeks to 8 weeks of fermentation, respectively. The same manner is also found in in vitro organic matter digestibility (IVOMD).
On the other hand, polyunsaturated fatty acid (PUFA)concentrate with some supplements that has been developed (Sulistyowati et al., 2013(Sulistyowati et al., , 2014(Sulistyowati et al., , and 2015 could be used as the base diet for incorporation of Durio zibethinus Murr peel powder fermented with Pleurotus ostreatus.  Sulistyowati et al. (2015).
Gross energy (GE) was generated from samples using Bomb Calorymeter. The contents of NDF and ADF were analyzed using the method of Goering and Van Soest (1970).
Volatile fatty acid (VFA) analysis and in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) were prepared as if that of in hidrolytic post ruminal fermentation after two timed 24 hours using the method of Tilley and Terry (1963) as reported by Sulistyowati et al. (2014). Using gas chromatography (GC) Shimadzu 2010 series, fatty acid methyl esters (FAME) were obtained There are several calculations, total short chain fatty acid (C4-C10), medium chain fatty acid (C12-C16), long chain fatty acid (C>16), mono unsaturated, poly unsaturated, saturated, unsaturated, ratio of PUFA/saturated, and unsaturated/saturated fatty acid (Schmidely et al., 2005 ).

Treatments and Experimental Design
This experiment was part of a research that has been splitted to several parameters as reported by Suciyanti et al. (2015) and Hartono et al. (2015), which then modified by combining with other feed ingredients to formulate a previously evaluated PUFA-concentrate (Sulistyowati et al., 2013(Sulistyowati et al., , 2014(Sulistyowati et al., , 2015. Experimental design in this research was Completely randomized design with four treatments of fermented Durio peel powder: F2; 2 weeks fermentation, F4: 4 weeks fermentation, F6: 6 weeks fermentation, and F8: 8 weeks fermentation and 4 replications. Data were analyzed for variance, any significant differences were further analyzed using Duncan Multiple Range Test (DMRT) as described by Lentner and Bishop (1986). Based on nutrient content from the previous results as reported by Suciyanti et al. (2015), especially crude protein that was higher (6.4%) than the ones of shorter fermentation duration or even the control one, the fermented Durio peel powder of 8 weeks was selected to be incorporated into PUFA-concentrate which then compared to PUFA-concentrate containing non fermented Durio peel powder.
These samples were then analyzed for their nutrient and fatty acid contents.
The data were analyzed descriptively. Other results showed that fermentation of coffee husk with P. ostreatus lowered VFA levels (173.79 mM in control decreased to 138.71 mM in 6% ration conataining this material) as reported by Badarina et al. (2014). The decreasing VFA of fermented coffee husk was also found by Xu et al. (2007).

VFA and GE Contents of
These durations of fermentation showed effects that there were improvements in ruminally in vitro of Durio zibethinus Murr peel powder. These VFA and N-NH3 performances are within normal ranges of 80-160 mm and 4-12 mM, respectively (Sutardi, 1977). However, these VFA levels showed opposite results of significantly (P<0.05) decreasing GE contents between 2 week and 8 week fermentation; eventhough quantitatively was very small amount (0.08 cal/g). While for the 4 and 6 weeks were remained the same as it was in 8 weeks of fermentation. Therefore, it could be stated that fermentation of Durio with P. ostreatus could be prolonged for up to 8 weeks as it was supported with higher VFA levels (105.37 mM in 2 weeks and 147.73 mM in 8 weeks).

Murr Peel Powder Fermented with P. ostreatus
In overall, fractions of fiber of all four treated fermented Durio zibethinus Murr peel powder fermented with P. ostreatus were not significantly different; however, the neutral detergent fiber (NDF) acid detergent fiber (ADF) tend to increase with the longer (in 2 and 8 weeks) the fermentation, as presented in Table 2.
On the other hand, these fractions are decreased in 4 weeks of fermentation, then increased in 6 and 8 weeks of fermentation. respectively as reported by Sulistyowati et al., 2015). Based on these two results, it is suggested that for ration containing high fraction of fiber, it needs fermentation with fungi for 6 weeks; while, for ration containing concentrate, lower fiber content, could be stored for the length of 2-6 weeks.  Table 3. Moisture, dry matter and ash contents of these two rations are quantitatively unchanged. However, organic matter, crude protein, ether extract and fiber fractions are improved. These nutrients are incresed quantitaively; while the NDF and ADF are decreased in fermented ration. These improved nutrients suggested that fermentation with P. osetreatus works well in breakdown lignin binding in Durio peel powder so that some nutrients available for the growth of the fungi which then improved the overall quality of of its nutrients. While, gross energy is remained relatively the same.  (Sulistyowati et al., 2015).