The accuracy of near infrared reflectance spectroscopy (NIRS) depends on the database generated from the conventional wet chemistry (CWC). Currently, the local database of fiber-source feeds for tropical dairy cattle are still limited. The study aimed to compare CWC and NIRS initial database (NIRSID) results, to predict CWC from NIRSID, and to improve the accuracy of NIRS prediction using local database (NIRSLD). Five feeds as sources of fiber (Napier grass, natural grass, corn leaves, corn husk, and rice straw) from 4 areas of dairy cattle farming were used (4 farms from each area). For external calibration, 20 independent Napier grass samples were tested. Samples were analyzed using NIRS and CWC to measure dry matter (DM), ash, crude protein (CP), ether extract (EE), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and silica (Si) to calculate hemicellulose, cellulose, and lignin contents. The results obtained by NIRSID were compared to those obtained by CWC using T-test. Predictions of CWC from the results obtained by NIRSID were attempted using regressions. The NIRSLD was developed by inputting the CWC value to NIRS spectrums. Internal calibration and validation as well as external calibration, were run. The results showed that NIRSID has low capacity in determining CWC (R2<0.683). Calibration using local database (NIRSLD) improved CWC prediction accuracy (residual predictive deviation (RPD) > 2 except for DM, EE, CF, ADL, and lignin). External validation showed that CWC and NIRSLD were similar in all parameters (p<0.05). The ratios of the standard error of prediction (SEP) to the standard error of laboratory (SEL) were > 2 for CP, CF, and ADF. It is concluded that the local database of NIRS of fibersource feeds is necessary to improve the prediction accuracy of local dairy fiber-source feeds values using NIRS.

Abstract. Pazla R, Jamarun N, Zain M, Yanti G, Chandra RH. 2021. Quality evaluation of tithonia (Tithonia diversifolia) with fermentation using Lactobacillus plantarum and Aspergillus ficuum at different incubation times. Biodiversitas 22: 3936-3942. This research aimed to evaluate the nutritional quality of tithonia (Tithonia diversifolia) fermented using Lactobacillus plantarum and Aspergillus ficuum with different incubation times on nutritional content, digestibility, phytase enzyme activity, and characteristics of rumen fluid. The research used an experimental method with a factorial completely randomized design to evaluate the nutritional content and phytase enzyme activity after fermentation (stage 1). A randomized block design was used to evaluate in vitro digestibility and rumen fluid characteristics (stage 2). For factorial completely randomized design, factor A is the type of microbe (L. plantarum and A. ficuum), then factor B is the incubation time (3,5,7 days). Parameters observed were the nutritional content of dry matter (DM), organic matter (OM), crude protein (CP), crude fiber (CF), and phytase enzyme activity. For the Randomized Block Design, the research treatments were A = A. ficuum + 5 days of incubation, B = A. ficuum + 7 days of incubation, C = L. plantarum + 3 days of incubation, D = L. plantarum + 5 days of incubation. Parameters measured were the digestibility of dry matter(DMD), organic matter (OMD), crude protein (CPD), crude fiber (CFD), rumen pH, VFA production, and NH3 rumen fluid. The results showed that there was an interaction between the type of microbe and incubation time. The treatment had a significantly different effect (P<0.05) on the content of OM, CP, CF and phytase enzyme activity, but no interaction with the content of DM treatment. In the digestibility, the results showed that the effect was not significantly different (P>0.05) on DMD, OMD, CPD but had a significant effect (P<0.05) on CFD. The treatments also had no significant effect (P>0.05) on VFA but were significantly different (P<0.05) on NH3. From this study, it can be concluded that fermented tithonia using A. ficuum with an incubation period of 7 days could improve the quality of tithonia. It can be seen from the content of CP (31.02%), CF (16.52%), phytase enzyme activity (37.36 U/ml), DMD (66.86%), OMD (67.36%), CFD (81.01%), CPD (70.37%), VFA production 135 mM and NH3 concentration 14.31 mg/100 ml, and pH value 6.72 which is suitable for rumen microbial growth.

Near Infrared Reflectance Spectroscopy (NIRS) accuracy is affected by its database. However, our previously developed database for dairy cattle dietary fiber feed (DFF) showed low accuracy for complex organic substance detection due to mixed-species used in the database. This paper aimed to compare single and mixed-species NIRS database accuracy in predicting DFF nutrient contents. In the mixed database, five feeds from three areas of dairy cattle farming were sampled. In the single database, thirty Napier grass from 30 areas were collected. Samples were analyzed chemo-metrically for their nutrient contents. Spectra of each sample were collected three times (two spectra for calibration and a spectrum for validation) using FT-NIRS Spectrometer Solid Cell. Calibration and validation models were carried out using the Partial Least Squares (PLS) regression. For external validation, seven independent Napier grass samples were tested. The result showed that the single species NIRS database developed using Napier grass was less accurate than mixed-species DFF due to huge nutrient content variations between varieties of Napier grass. It is concluded that database accuracy developed from mixed dietary fiber feed were more accurate in comparison to single species and suggested to used combination of mixed and single database for more accurate DFF prediction.