36 Picture 2.The leaves, fruit and bark of Dipterocarpusgrandiflorus Blanco.
Among the Shoreae tribe, Shorea dasyphylla Foxw is the most dominant species in the Soraya research station. This species is known as Light Red
Meranti. According to IUCN list, this species is endangered [4]. Actually, Dipterocarpus
and Shorea genera were mostly well known in the timber world trade [6]. All shorea members which were found in this research area
S. dasyphylla Foxw., S. johorensis Foxw., S. lepidota Korth. Blume., and S. palembanica
Miq. belong to Red Meranti Picture 3.
a b
c Picture 3. a Red Meranti bark and buttress, b S. palembanica, c S.
johorensis
4. Conclusion
Based on the inventory of Dipterocarpaceae species in Soraya Research Station, we found that:
Dipterocarpaceae family in Soraya research station was dominated with
Dipterocarpoideae sub family. There were 11 species of Dipterocarpaceae which belonged to
Dipterocarpeae tribe Dipterocarpus genus and Shoreae tribe Shorea, Parashorea
and Hopea genera
37 The Most dominant species found in the research area was Hopea
dryobalanoides Miq 73 species meanwhile the less species found are
Dipterocarpus rigidus Ridl 2 species and Dipterocarpus cornutus Dyer
2 species.
5. References
[1] P.S. Ashton. 1982. Dipterocarpaceae. In: M.D. Dssanayake, F.R. Fosberg eds Arevised handbook to the flora of ceylon I.
Smithsonnian Institute Press, Washington, D.C. pp 364 – 423.
[2] S. Apanah. 1993. Mass flowering of dipterocarp forests in a seasonal tropics. J. Of Bioscie. 18 4: 457
– 474. [3] C.P. Cao. 2006. Genetic variation of the genus Shorea
Dipterocarpaceae in Indonesia. PhD. Thesis. Georg-August Universitaat, Goettingen.
[4] Leuser Management Unit LMU. 1997. Annual Report of Soraya Research Station, Medan.
[5] http:www.iucnredlist.orgsearch [6] I. Kartasujana, A. Martawijaya. 1979. Kayu Perdagangan Indonesia,
Sifat dan Kegunaannya. Lembaga penelitian Hutan, Bogor.
38
Influence of different supplemental niacin levels on intake, digestibility and rumen fermentation of dairy cows: a meta-
analysis
Rossy E. A. Anggreini
1
, Erika B. Laconi
2
, Anuraga Jayanegara
2,
1
Graduate School of Nutrition and Feed Science, Bogor Agricultural University, Bogor, 16680, Indonesia
2
Department of Nutrition and Feed Technology, Bogor Agricultural University, Bogor, 16680, Indonesia
Corresponding email: anu_jayanegarayahoo.com
Abstract
Rumen microbes can synthesis niacin but at fewer amount. Niacin is occasionally supplemented into dairy cows’ ration to improve their
production performance especially during early lactation period. The present study was aimed to assess the effect of different supplemental niacin
levels on intake, digestibility and rumen fermentation of dairy cows through a meta-analytical study. A database was constructed from published
literatures reporting niacin supplementation on dairy cows. A total of 49 studies from 46 published articles were integrated into the database.
Different niacin levels at various supplemental levels were specified, i.e. 0 to 24 mg; nutrient intake and rumen fermentation parameters were
integrated as well. Data were analyzed by a mixed model methodology in which different studies were treated as random effects whereas niacin levels
were treated as fixed effects. The significant effect was stated when P0.05. When a parameter showed 0.05P0.1, then the effect was considered to
have a tendency to be significant. The results showed that different levels of niacin supplementation did not significantly influence nutrient intake,
digestibility and rumen fermentation of dairy cows P0.05. It is concluded that supplementation of niacin has less effect in improving intake,
digestibility and rumen fermentation. Keywords
meta-analysis, niacin, concentration, dairy cow
1. Introduction
Dairy cows require supplementation of niacin in the diet at sufficient levels because the rumen microbes can produce niacin in small amounts only.
Niacin plays a role in generating energy in the Krebs cycle ATP cycles [1]. Energy deficiency leads to body fat mobilization of dairy cows to be used
as energy and then increases beta-hidroxybutiric acid concentration; this condition stimulates ketosis, a metabolic disorder, to occur [2]. It is
