EFFECT OF SUPPLEMENTARY UREA, GLUCOSE AND MINERALS ON THE IN VITRO DEGRADATION OF LOW QUALITY FEEDS

Oosting, S.J.,Verdonk, J.M.H.J.,Spinhoven, G.G.B. Asian Australasian Association of Animal Productio 1989 Animal Bioscience Vol.2 No.4

Increasing levels of ammonia-N in the rumen fluid used for in vitro incubation were achieved by supplementation of the ration of the donor cows with urea and by addition of urea either with or without glucose to the rumen fluid after collection. The ration of the donor animals consisted of wheat straw (80%) and maize silage (20%). During the second half of the experiment the basal ration was supplemented with a mineral mixture. Wheat straw, Guinea grass and two rice straw varieties were incubated with the various kinds of rumen fluid. Parameters studied were: solubility, apparent organic matter disappearance after 48 hours of incubation ($OMD_{48}$), rate of organic matter degradation from 0 to 24 hours of incubation ($k_1$) and from 24 to 95 hours ($k_2$). The concentration of ammonia-N in the rumen fluid at which 95% of the maximal $OMD_{48}$ and k1 were reached (88.2 and 100.0 mg/l) were independent of the feed. With regard to the $k_2$ the required ammonia-N concentration to reach 95% of the maximal $k_2$ differed per feed. Mineral supplementation increased the OMD48 and $k_1$, but not the solubility and $k_2$. Glucose addition in combination with urea had no beneficial effect compared to urea supplementation alone.

Effects of Type and Level of Forage Supplementation on Voluntary Intake, Digestion, Rumen Microbial Protein Synthesis and Growth in Sheep Fed a Basal Diet of Rice Straw and Cassava

Premaratne, Sujatha,van Bruchem, J.,Chen, X.B.,Perera, H.G.D.,Oosting, S.J. Asian Australasian Association of Animal Productio 1998 Animal Bioscience Vol.11 No.6

An experiment was conducted with eight growing sheep (average initial weight 20.6 kg and average final weight 23.7 kg) in a $4{\times}4$ Latin square design to study the effect of type of forage supplementation to a basal diet of rice straw (ad libitum) and cassava (Manihot esculanta, approximately 9 g of dry matter $(DM).kg^{-0.75}{\cdot}day^{-1}$) on voluntary intake, digestion, rumen microbial protein synthesis and daily weight gain. Forages used were Leucaena (L, Leucaena leucocephala), Gliricidia (G, Gliricidia maculata) and Tithonia (T, Tithonia diversifolia, wild sunflower) at a DM supplementation level of approximately $13g.kg^{-0.75}.day^{-1}$. Organic matter intake was 40.4, 55.5, 55.0 and $54.9g{\cdot}kg.^{-0.75}{\cdot}day^{-1}$ for control (C, ad libitum straw and cassava), L, G and T. respectively, significantly lower for C than for the supplemented diets. Intake of supplementary forage had also a significantly positive effect on voluntary rice straw intake. All forage supplemented diets showed a significantly higher whole diet organic matter digestion than C ($488g{\cdot}kg^{-1}$), while T ($557g{\cdot}kg^{-1}$) differed significantly from L ($516g{\cdot}kg^{-1}$) but not from G ($526g{\cdot}kg^{-1}$). Daily weight gain was -1.7, 5.2, 5.4 and $4.7g{\cdot}kg^{-0.75}$, for C, L, G and T. respectively, significantly lower for C than for the forage-supplemented diets. Efficiency of microbial protein synthesis estimated from urinary excretion of purine derivatives was lower for C (3.8 g microbial N. (kg digestible organic matter intake $(DOMI))^{-1}$ than for the forage supplemented diets (11.3, 9.0 and 9.4 g microbial $N.(kg\;DOMI)^{-1}$ for L, G and T. respectively).

Predicting nutrient excretion from dairy cows on smallholder farms in Indonesia using readily available farm data

Zahra Windi Al,Middelaar Corina E. van,de Boer Imke J. M.,Oosting Simon J. 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.12

Objective: This study was conducted to provide models to accurately predict nitrogen (N) and phosphorus (P) excretion of dairy cows on smallholder farms in Indonesia based on readily available farm data. Methods: The generic model in this study is based on the principles of the Lucas equation, describing the relation between dry matter intake (DMI) and faecal N excretion to predict the quantity of faecal N (QFN). Excretion of urinary N and faecal P were calculated based on National Research Council recommendations for dairy cows. A farm survey was conducted to collect input parameters for the models. The data set was used to calibrate the model to predict QFN for the specific case. The model was validated by comparing the predicted quantity of faecal N with the actual quantity of faecal N (QFNACT) based on measurements, and the calibrated model was compared to the Lucas equation. The models were used to predict N and P excretion of all 144 dairy cows in the data set. Results: Our estimate of true N digestibility equalled the standard value of 92% in the original Lucas equation, whereas our estimate of metabolic faecal N was –0.60 g/100 g DMI, with the standard value being –0.61 g/100 g DMI. Results of the model validation showed that the R2 was 0.63, the MAE was 15 g/animal/d (17% from QFNACT), and the RMSE was 20 g/animal/d (22% from QFNACT). We predicted that the total N excretion of dairy cows in Indonesia was on average 197 g/animal/d, whereas P excretion was on average 56 g/animal/d. Conclusion: The proposed models can be used with reasonable accuracy to predict N and P excretion of dairy cattle on smallholder farms in Indonesia, which can contribute to improving manure management and reduce environmental issues related to nutrient losses.

Type III CRISPR-Cas - from Structure-function Analyses to Diagnostics

Jurre A. STEENS,Yifan ZHU,John VAN DER OOST,Raymond H.J. STAALS 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.4

Molecular insights into DNA interference by CRISPR-associated nuclease-helicase Cas3

Gong, Bei,Shin, Minsang,Sun, Jiali,Jung, Che-Hun,Bolt, Edward L.,van der Oost, John,Kim, Jeong-Sun National Academy of Sciences 2014 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.111 No.46

<P><B>Significance</B></P><P>Bacteria can repel invader DNA and RNA molecules by using an adaptive immunity mechanism called clustered regularly interspaced short palindromic repeats (CRISPRs)-Cas. CRISPR loci in a host genome are a repository of DNA fragments obtained from previous encounters with an invader, which can be transcribed and activated into short RNA molecules (crRNA) with sequences complementary to invader DNA or RNA. In some CRISPR-Cas systems, crRNA is assembled into a targeting complex called “Cascade” that seeks invader DNA to form an R-loop that triggers recruitment of a nuclease-helicase, Cas3, to destroy invader DNA. In this study, we show atomic resolution structures of a full-length Cas3, revealing how Cas3 coordinates binding, ATP-dependent translocation, and nuclease digestion of invader DNA.</P><P>Mobile genetic elements in bacteria are neutralized by a system based on clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins. Type I CRISPR-Cas systems use a “Cascade” ribonucleoprotein complex to guide RNA specifically to complementary sequence in invader double-stranded DNA (dsDNA), a process called “interference.” After target recognition by Cascade, formation of an R-loop triggers recruitment of a Cas3 nuclease-helicase, completing the interference process by destroying the invader dsDNA. To elucidate the molecular mechanism of CRISPR interference, we analyzed crystal structures of Cas3 from the bacterium <I>Thermobaculum terrenum</I>, with and without a bound ATP analog. The structures reveal a histidine-aspartate (HD)-type nuclease domain fused to superfamily-2 (SF2) helicase domains and a distinct C-terminal domain. Binding of ATP analog at the interface of the SF2 helicase RecA-like domains rearranges a motif V with implications for the enzyme mechanism. The HD-nucleolytic site contains two metal ions that are positioned at the end of a proposed nucleic acid-binding tunnel running through the SF2 helicase structure. This structural alignment suggests a mechanism for 3′ to 5′ nucleolytic processing of the displaced strand of invader DNA that is coordinated with ATP-dependent 3′ to 5′ translocation of Cas3 along DNA. In agreement with biochemical studies, the presented Cas3 structures reveal important mechanistic details on the neutralization of genetic invaders by type I CRISPR-Cas systems.</P>