• 제목/요약/키워드: W-substitution

검색결과 190건 처리시간 0.04초

인공 신경망 알고리즘을 활용한 플라이애시 콘크리트의 염해 내구성능 예측 (The Prediction of Durability Performance for Chloride Ingress in Fly Ash Concrete by Artificial Neural Network Algorithm)

  • 권성준;윤용식
    • 한국구조물진단유지관리공학회 논문집
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    • 제26권5호
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    • pp.127-134
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    • 2022
  • 본 연구에서는 장기재령(4~6년)으로 양생된 플라이애시 콘크리트를 대상으로 촉진 염화물 이온 통과 시험을 수행하였다. 콘크리트 배합은 3수준의 물-결합재 비(0.37, 0.42, 0.47)와 2수준의 플라이애시 치환율(0, 30 %)을 가지고 있었으며, 시간 의존적으로 개선되는 통과 전하량을 정량적으로 분석하였다. 또한 실험결과를 GRU 알고리즘을 고려한 단별량 시계열 모델을 적용하여 학습하였으며, 그 예측값을 평가하였다. 통과전하량 실험 결과, 플라이애시 콘크리트는 물-결합재 비에 의한 통과 전하량의 변화가 재령이 증가함에 따라 점차 감소하였으며 OPC 콘크리트에 비하여 우수한 염해저항성을 나타내었다. 최종 평가일인 6년에서 플라이애시 콘크리트는 모든 물 결합재 비 조건에서 'Very low' 등급에 해당되는 통과 전하량이 평가되었지만, OPC 콘크리트의 경우 가장 높은 물-결합재 비를 갖는 조건에서 'Moderate' 등급을 나타내었다. 메인 알고리즘으로서 사용한 GRU 알고리즘은 시계열 데이터를 분석할 수 있고 연산 속도가 빠른 장점을 갖고 있다. 4개의 은닉층을 갖는 딥-러닝 모델이 고려되었으며 결과값은 실험값을 합리적으로 예측하고 있었다. 본 연구의 딥-러닝 모델은 단변량 시계열 특성만을 고려할 수 있는 한계점이 존재하지만 추가 연구를 통해 콘크리트의 강도 및 확산계수와 같은 다양한 특성을 고려할 수 있는 모델이 개발 중에 있다.

Carcinogenicity and mutagenicity of heterocyclic amines in transgenic models

  • Ryu D.Y.
    • 한국독성학회:학술대회논문집
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    • 한국독성학회 2000년도 국제심포지움 및 추계학술대회
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    • pp.45-67
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    • 2000
  • 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is a mutagenic and carcinogenic heterocyclic amino found in cooked meat. The in vivo mutagenicity and hepatocarcinogenicity of MeIQx were examined in mice harboring the lacZ mutation reporter gene ($Muta^{TM}$ Mice) and bitransgenic mice over-expressing the c-myc oncogene. C57B1/$\lambda$lacZ and bitransgenic c-myc (albumin promoter)/$\lambda$lacZ mice were bred and weaned onto an AIN-76 based diet containing $0.06\%$ (w/w) MeIQx or onto control diet. After 30 weeks on diet, only male bitransgenic mice on MeIQx developed hepatocellular carcinoma ($100\%$ incidence) indicating that there was synergism between c-myc over-expression and MeIQx. By 40 weeks, hepatic tumor incidence was $100\%$ ($17\%$) and $44\%$ ($0\%$) in male c-myc/$\lambda$lacZ and C57B1/$\lambda$lacZ mice given MeIQx (or control) diet, respectively, indicating that either MeIQx or c-myc over-expression alone eventually induced hepatic tumors. At either time point, mutant frequency in the lacZ gene was at least 40-fold higher in MeIQx-treated mice than in control mice of either strain. These findings suggest that MeIQx-induced hepatocarcinogenesis is associated with MeIQx-induced mutations. Elevated mutant frequency in MeIQx-treated mice also occurred concomitant with the formation of MeIQx-guanine adducts as detected by the $^{32}P$-postlabeling assay. Irrespective of strain or diet, sequence analysis of the lacZ mutants from male mouse liver showed that the principal sequence alteration was a single guanine-base substitution. Adenine mutations, however, were detected only in animals on control diet. MeIQx-fed mice harboring the c-myc oncogene showed a l.4-2.6-fold higher mutant frequency in the lacZ gene than mice not carrying the transgene. Although there was a trend toward higher adduct levels in c-myc mice, MeIQx-DNA adduct levels were not significantly different between c-myc/$\lambda$lacZ and C57B1/$\lambda$lacZ mice after 30 weeks on diet. Thus, it appeared that factors in addition to MeIQx-DNA adduct levels, such as the enhance rate of proliferation associated with c-myc over-expression, may have accounted for a higher mutant frequency in c-myc mice. In the control diet groups, the lacZ mutant frequency was significantly higher in c-myc/$\lambda$lacZ mice than in 057B1/$\lambda$1acZ mice. The findings are consistent with the notion that c-myc over-expression is associated with an increase in mutagenesis. The mechanism for the synergistic effects of c-myc over-expression on MeIQx hepatocarcinogenicity appears to involve an enhancement of MeIQx-induced mutations.

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탄수화물의 급원과 식이섬유의 종류를 달리한 식이가 제 2형 당뇨 쥐의 당대사 및 지질대사에 미치는 영향 (Effect of Feeding with Different Source of Carbohydrate and Fiber on Carbohydrate and Lipid Metabolism in Type 2 Diabetic Rats)

  • 권상희;정혜진;심지애;손영애;김미경
    • 한국식생활문화학회지
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    • 제22권1호
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    • pp.157-165
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    • 2007
  • This study was designed to evaluate the effects of fructose(F) or sucrose(S) and guar gum intake on carbohydrate and lipid metabolism in 15-week-old male Goto-Kakizaki(GK) rats. Fifty rats were randomly assigned to 5 groups which were different in carbohydrate(25% of carbohydrate) and fiber(5% w/w) sources. The carbohydrate(CHO) sources of each group were comstarch(control group, 100% of CHO), fructose with cellulose(F), fructose with guar gum(FG), sucrose with cellulose(S), and sucrose with guar gum(SG). Each group was fed exterimental diet for 4 weeks. We measured food intake, body weight gain, adipose tissues weight and organs weight. We conducted oral glucose tolerance test(OGTT) and measured plasma insulin concentration to examine carbohydrate metabolism. To evaluate lipid metabolism, we measured the lipid profile of plasma, liver and feces. Food intake and weight gain of FG or SG groups tended to be less than those of F or S groups. Perirenal and epididymal fat pad weights of SG group were significantly lower than those of S group and those of FG group tended to be lower than those of F group. In OGTT, blood glucose values of F or S groups were significantly higher than those of C group, and FG or SG groups tended to be lower than those of F or S groups during the experimental time. The area under the curve(AUC) of C group was significantly highest among the groups, AUC and plasma insulin concentration of FG or SG groups tended to be lower than those of F or S groups. Plasma and hepatic triglyceride (TG) of FG and SG groups were significantly lower than those of F and S groups, plasma and hepatic total lipid(TL) and total cholesterol(TC) of FG and SG groups tended to be lower than those of F and S groups. Fecal TL, TG and TC of FG or SG groups tended to be higher than those of F and S groups. In conclusion, intake of guar gum should improve carbohydrate and lipid metabolism in partial substitution of fructose or sucrose for cornstarch in GK rats.

조강형 혼화제에 의한 플라이애시 다량 치환 콘크리트의 품질 향상 (Quality Improvement of High Volume Fly Ash Concrete due to Early Strength Gain Admixture)

  • 한천구;박종호;이정아
    • 한국건설순환자원학회논문집
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    • 제4권4호
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    • pp.117-124
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    • 2009
  • 본 연구에서는 FA 다량 치환 콘크리트의 품질 개선 및 기타 품질 향상을 목적으로 선행 연구에서 개발된 조강형 혼화제(GA)로 FA 다량 치환 콘크리트의 품질 향상 가능성을 평가하였다. 실험은 우선 FA 15%를 치환한 배합에 나프탈렌계 혼화제(이하 NA)를 사용한 것을 Plain으로 하였고, FA 20, 25% 및 30%를 치환한 경우, GA를 사용하여 콘크리트의 제반특성을 Plain과 비교 실험 하였다. 굳지 않은 콘크리트 특성으로 유동성은 GA를 사용할 경우 저하하므로 그 사용량을 증가시켜주어야 하는데, 단 W/B 60%의 경우는 Plain 보다 슬럼프 로스가 약 35~70 mm 감소하여 유리한 것으로 나타났다. 공기량은 FA 사용량 증가에 따라 FA에 포함된 미연소탄분의 AE제 흡착작용에 기인하여 감소함으로서 AE제 사용을 비례적으로 증가시켜 주어야함을 알 수 있었다. 블리딩은 FA 20%에서 블리딩 발생량이 가장 적게 나타나 블리딩 저감 효과를 기대할 수 있었다. 경화 콘크리트의 특성으로 응결시간은 GA를 사용한 경우 Plain과 동등한 수준으로 나타나, 응결 지연현상을 줄일 수 있는 것으로 판단된다. 압축강도는 W/B 및 양생온도와 관계없이 GA를 사용한 경우 Plain과 동등한 강도 발현을 확인 할 수 있었으나, FA 30% 치환한 경우는 사용상에 주의가 필요할 것으로 사료된다. 동결융해 저항성은 Plain보다 초기 값이 작게 나타났으나, 전반적으로 큰 차이가 아니기 때문에 내동해성 문제가 없을 것으로 판단된다. 촉진 중성화는 GA를 사용함에 따라, FA를 다량 사용할 경우 단점으로 지적되는 중성화 취약에 대한 문제는 어느 정도 해결 할 수 있을 것으로 분석되었다.

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완두 전분을 첨가한 국수의 품질특성 (A study on the noodle quality made from pea starch-wheat composite flour)

  • 김은주;윤재영;김희섭
    • 한국식품조리과학회지
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    • 제18권6호
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    • pp.692-697
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    • 2002
  • 밀가루에 배합비를 달리하여 완두전분을 대체한 완두 전분 복합분의 제면성을 조사한 결과는 다음과 같다. 완두 전분 첨가 복합분을 이용하여 만든 dough와 cooked dough를 rheometer를 이용하여 기계적 측정을 한 결과 hardness, springiness, gumminess는 시료간에 유의차가 없었으며 cohesiveness만이 밀이 51.6%로 가장 높아 다른 대체전분과 유의성이 있었다. (p<0.05) 국수의 조리특성중 삶은 국수의 무게 증가량은 시료간에 차이가 없었으나, 조리 손실율은 밀가루 국수가 가장 낮게 나타났고 P20이 가장 높게 나타났다. 색차계를 이용하여 색도를 측정한 결과 P30의 L값은 가장 높게 b값은 가장 낮게 나타났다. C20은 P30에 비해 L 값은 낮았으나 b값은 비슷했고 밀은 가장 낮은 L값과 가장 높은 b값을 나타내었다. 완두전분을 많이 첨가할수록 색이 밝아지고 황색도가 낮아졌다. 조리된 국수는 완두전분을 첨가했을 때 transparency가 유의적으로 높았으며 hardness에서는 유의적 차이가 없었다. P30에서는 smoothness가 유의적으로 낮게 나타났다. Stickiness, chewiness, acceptability에서는 시료간에 유의적 차이가 없었다. P20은 모든 관능적 특성에서 밀가루면과 비슷한 특성을 나타냈으며 국수를 삶았을 때 transparency가 높았다. C20은 P20, P30보다 hardness가 유의적으로 낮거나 smoothness가 높았다. 국수를 국수장국에 말아 10분간 방치한 후의 관능평가에서도 P20은 모든항목에서 P30은 aceeptablity를 제외한 모든 항목에서 W와 유의차가 없었다. 이상의 결과로 볼 패 완두 전분의 조리된 국수의 swelling 방지 효과는 기대할 수 없었으나 20% 대체한 P20이 완두 전분 첨가면으로서 적합하였다.e proportion of 1st principal component was 0.818 in ESI-flavored oil. The PCA plot was used to detect stored Elsholtzia splendens flavored oils.(앞 뒤 문맥이 안맞음. 뒤에 이어지는 글이 있는지?).철저한 위생관리가 요구되어졌다.안한다고 답한 비율은 남자가 여자보다 높게 나타났으며(p < 0.05), 저체중군의 편식율이 가장 높게 나타났다. 한편, 식사의 질에 대하여 식사를 고칠 필요가 있다고 답한 비율은 남자가 40.4%, 여자가 56.3%로 나타났으며 (p < .0.01), 다른 군에 비하여 저체중군 남자와 과체중군 여자에게서 높게 나타났다. 4. 수면 시간은 남자는 평균 6.92시간, 여자는 6.53시간으로 조사되었으며, 과체중군 남자가 가장 길었으며, 저 체중군 여자가 가장 짧은 것으로 조사되었다. 수면시간에 관해서 남녀 모두 적당하다는 비율이 가장 높았다. 한편 하루 중 노동, 운동, 휴식, 식사의 균형에 관해서 남녀 모두 가끔 그렇다고 응답한 비율이 높게 나타났으며 전혀 아니라고 응답한 비율도 모든 체형에서 24%이상으로 나타났다. 남자의 70.2%,여자의 52.3%는 운동을 하고 있는 것으로 조사되었으며(p < 0.001) 남자는 체형과 상관없이 운동을 가끔하는 비율이 가장 높았으며, 전혀 운동을 하지 않는 비율도 24% 이상으로 나타났다. 여자의 경우 운동을 항상 하고 있는 비율은 저체중군에서, 가끔 하는 비율은 과체중군에서 높게 나타났다. 자각적 건강 상태에 관하여 남녀 모두 과반수 이상이 그저 그렇다고 응답하였으며 건강하여 문제가 없다는 남자에게서, 항상 피곤하고 건강 장애가 있다는 여자에게서 높게 나타났다(p < 0.05). 항상 피곤하고 건강 장애가 있다고 응답한 경우는 과체중군 남자와 표준체중군 여자에게서

Cloning and Expression of FSHb Gene and the Effect of $FSH{\beta}$ on the mRNA Levels of FSHR in the Local Chicken

  • Zhao, L.H.;Chen, J.L.;Xu, H.;Liu, J.W.;Xu, Ri Fu
    • Asian-Australasian Journal of Animal Sciences
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    • 제23권3호
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    • pp.292-301
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    • 2010
  • Follicle-stimulating hormone (FSH) is a pituitary glycoprotein hormone that is encoded by separate alpha- and betasubunit genes. It plays a key role in stimulating and regulating ovarian follicular development and egg production in chicken. FSH signal transduction is mediated by the FSH receptor (FSHR) that exclusively interacts with the beta-subunit of FSH, but characterization of prokaryotic expression of the FSHb gene and its effect on the expression of the FSHR gene in local chickens have received very little attention. In the current study, the cDNA fragment of the FSHb gene from Dagu chicken was amplified using reverse transcription polymerase chain reaction (RT-PCR), and inserted into the pET-28a (+) vector to construct the pET-28a-FSHb plasmid. After expression of the plasmid in E. coli BL21 (DE3) under inducing conditions, the recombination protein, $FSH{\beta}$ subunit, was purified and injected into the experimental hens and the effect on the mRNA expression levels of the FSHR gene was investigated. Sequence comparison showed that the coding region of the FSHb gene in the local chicken shared 99%-100% homology to published nucleotides in chickens; only one synonymous nucleotide substitution was detected in the region. The encoded amino acids were completely identical with the reported sequence, which confirmed that the sequences of the chicken FSHb gene and the peptides of the $FSH{\beta}$ subunit are highly conserved. This may be due to the critical role of the normal function of the FSHb gene in hormonal specificity and regulation of reproduction. The results of gene expression revealed that a recombinant protein with a molecular weight of about 19 kDa was efficiently expressed and it was identified by Western blotting analysis. After administration of the purified $FSH{\beta}$ protein, significantly higher expression levels were demonstrated in uterus, ovary and oviduct samples (p<0.05). These observations suggested that the expressed $FSH{\beta}$ protein possesses biological activity, and has a potential role in regulation of reproductive physiology in chickens.

Genetic Organization of the hrp Genes Cluster in Erwinia pyrifoliae and Characterization of HR Active Domains in HrpNEp Protein by Mutational Analysis

  • Shrestha, Rosemary;Park, Duck Hwan;Cho, Jun Mo;Cho, Saeyoull;Wilson, Calum;Hwang, Ingyu;Hur, Jang Hyun;Lim, Chun Keun
    • Molecules and Cells
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    • 제25권1호
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    • pp.30-42
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    • 2008
  • The disease-specific (dsp) region and the hypersensitive response and pathogenicity (hrp) genes, including the hrpW, $hrpN_{Ep}$, and hrpC operons have previously been sequenced in Erwinia pyrifoliae WT3 [Shrestha et al. (2005a)]. In this study, the remaining hrp genes, including the hrpC, hrpA, hrpS, hrpXY, hrpL and hrpJ operons, were determined. The hrp genes cluster (ca. 38 kb) was comprised of eight transcriptional units and contained nine hrc (hrp conserved) genes. The genetic organization of the hrp/hrc genes and their orientation for the transcriptions were also similar to and collinear with those of E. amylovora, showing ${\geq}80%$ homologies. However, ORFU1 and ORFU2 of unknown functions, present between the hrpA and hrpS operons of E. amylovora, were absent in E. pyrifoliae. To determine the HR active domains, several proteins were prepared from truncated fragments of the N-terminal and the C-terminal regions of $HrpN_{Ep}$ protein of E. pyrifoliae. The proteins prepared from the N-terminal region elicited HR, but not from those of the C-terminal region indicating that HR active domains are located in only N-terminal region of the $HrpN_{Ep}$ protein. Two synthetic oligopeptides produced HR on tobacco confirming presence of two HR active domains in the $HrpN_{Ep}$. The HR positive N-terminal fragment ($HN{\Delta}C187$) was further narrowed down by deleting C-terminal amino acids and internal amino acids to investigate whether amino acid insertion region have role in faster and stronger HR activity in $HrpN_{Ep}$ than $HrpN_{Ea}$. The $HrpN_{Ep}$ mutant proteins $HN{\Delta}C187$ (D1AIR), $HN{\Delta}C187$ (D2AIR) and $HN{\Delta}C187$ (DM41) retained similar HR activation to that of wild-type $HrpN_{Ep}$. However, the $HrpN_{Ep}$ mutant protein $HN{\Delta}C187$ (D3AIR) lacking third amino acid insertion region (102 to 113 aa) reduced HR when compared to that of wild-type $HrpN_{Ep}$. Reduction in HR elicitation could not be observed when single amino acids at different positions were substituted at third amino acids insertion region. But, substitution of amino acids at L103R, L106K and L110R showed reduction in HR activity on tobacco suggesting their importance in activation of HR faster in the $HrpN_{Ep}$ although it requires further detailed analysis.

복분자 발효주의 양조특성 (Alcoholic Fermentation of Bokbunja (Rubus coreanus Miq.) Wine)

  • 최한석;김명곤;박효숙;김용석;신동화
    • 한국식품과학회지
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    • 제38권4호
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    • pp.543-547
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    • 2006
  • 복분자 딸기의 일반성분은 수분 86.5%, 조단백 0.2%, 조지방 0.9%, 조섬유 6.6%, 회분 0.5%, $10^{\circ}Brix$정도의 당함량을 가지고 있었으며, 착즙액의 유리당은 fructose(2.99%), glucose(2.53%) 및 sucrose(0.07%)로 구성되어 있었다. Citric acid(14.57 mg/mL)와 malic acid(2.24 mg/mL)가 주요유기산 성분이었으며, shikimic, pyroglutamic, oxalic 순으로 미량 함유되어있었다. 본 실험에 이용된 3가지 균주중 Sc-24 균주가 복분자 발효에 적당한 것으로 판단되었으며, 발효시 오염방지를 위한 아황산 종류로는 $K_2S_2O_5$ 200 ppm 첨가가 양호하였다. Sc-24균주의 알코올 생산력은 $18-28^{\circ}Brix$의 당농도 범위에서 당농도에 비례적으로 증가하여 9.2-14.8%의 범위를 나타내었다. 매실즙의 첨가는 발효초기 복분자주 색상향상에 상당한 영향을 미치는 것으로 나타났으나 발효과정을 거치면서 색상 개선에 뚜렷한 영향을 볼 수는 없었다. 발효주의 유기산성분은 citric acid와 malic acid가 주요성분으로 발효과정에 의하여 상당량 감소되었고 formic acid와 acetic acid가 생성되었다. 씨를 포함하고 있지 않은 과즙 펄프나 과즙 상태로 발효시켰을 때 떫은맛이 약간 감소하였으며, 설탕의 용해처리는 외관상 주류의 품질에 영향을 미치지 않았다.

Effects of Sorghum Tannins, a Tannin Binder (Polyvinylpyrrolidone) and Sorghum Inclusion Level on the Performance of Broiler Chicks

  • Ambula, M.K.;Oduho, G.W.;Tuitoek, J.K.
    • Asian-Australasian Journal of Animal Sciences
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    • 제14권9호
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    • pp.1276-1281
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    • 2001
  • The feeding values of four indigenous Kenyan sorghum cultivars and the effects of polyvinylpyrrolidone (PVP) on the utilization of high tannin sorghum by broiler chicks were studied in two 3-week feeding trials. In Experiment 1, one hundred and five broiler chicks (initial average weight 97 g) were randomly assigned to each one of the seven grain-soybean meal diets. The diets consisted of maize [diet 1; no assayable tannin], white sorghum [diet 2; 0.59% catechin equivalents (CE)], cream sorghum [diet 3; 0.94% CE], light brown sorghum [diet 4; 2.71% CE] and dark brown sorghum [diet 5; 3.54% CE]. Diets 6 and 7 were included to test the possibility of overcoming the detrimental effects of sorghum tannins by adding PVP at 0.25% and 0.5% to dark brown sorghum, which resulted in dietary tannin levels of 3.46% and 3.38% CE respectively. In Experiment 2, the effects of tannin on dry matter digestibility (DMD) and nitrogen (N) retention were studied in a 3-week substitution assay in which high tannin sorghum (5% CE) was substituted for white maize at different inclusion levels. Ninety broiler chicks aged 7 days (initial average weight 102 g) were randomly assigned to each one of the six diets. The diets consisted of corn gluten meal and fishmeal as protein sources plus maize [diet 1] and high tannin sorghum at different inclusion levels [diets 2, 3, 4, 5 and 6], resulting in dietary tannin levels of 0, 1.25%, 1.66%, 2.08%, 2.5% and 3.2% CE respectively. Feed intake, feed efficiency and body weight gain were measured weekly. In Experiment 2, tannin absorption, DMD and N retention were measured on days 19, 20 and 21. The results of Experiment 1 showed that feed intake, feed efficiency and body weight gain were all affected by treatment (p<0.05). Diets 1, 2 and 3 gave similar body weight gains and all were better than diets 4 and 5 (i.e. 504, 517, 473 g, vs. 256, 267 g). Similarly, feed efficiencies were higher (p<0.05) for diets 1, 2 and 3 compared to diets 4 and 5 (0.4, 0.42, 0.39 vs. 0.21, 0.23). When 0.25% PVP was added to the dark brown sorghum (diet 6) there was no significant improvement in chick performance (p>0.05). However, addition of 0.5% PVP (diet 7) resulted in significant improvement (p<0.05) in body weight gain compared to the untreated dark brown sorghum. Overall, PVP did not completely overcome the deleterious effects of tannins. The results of Experiment 2 indicate that sorghum inclusion level and subsequent tannin level had no effect on feed intake, feed efficiency, weight gain, DMD and N retention. The above results suggest that tannin level should be limited to below 2.71% CE in broiler chick diets containing 20% CP and 0.4% methionine. However, in diets with 23% CP and 0.8% methionine tannin level of up to 3.2% will not affect performance. Consequently high tannin sorghum (5% CE) can be used to substitute for white maize by up to 100% in broiler chick diets.

Effect of Graded Levels of Green Grass Supplementation on Nutrient Digestibility, Rumen Fermentation and Microbial Nitrogen Production in Cattle Fed Rice Straw Alone

  • Chowdhury, S.A.;Huque, K.S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제10권5호
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    • pp.460-470
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    • 1997
  • On an absolute straw diet, the effect of graded levels of green grass supplementation on intake, nutrient digestibility, rumen fermentation pattern and microbial N yield has been studied in cattle. Of the two trials conducted, 16 intact growing bulls of 304 kg weight and 32 months old, randomly allocated to four treatments in a completely randomized design in the 1st trial. While, in the, 2nd trial, four rumen cannulated local bulls of about 60 months old and 400 kg weight were used in a $4{\times}4$ Latin square design with four treatments in four periods. In both the trials, in addition to a mineral mixture, animals were supplemented with graded levels of naturally grown green grass of 0 kg (T1), 2 kg (T2), 4 kg (T3) or 6 kg (T4) to an ad libitum rice straw diet In the 1st trial, measurements were made on intake digestibility, growth rate, N balance and microbial N yield. While in the 2nd trial, in addition to the above parameters (except growth rate), rumen parameters were also studied. All levels of grass supplementation decreased the straw DM intake and increased the substitution rate. The rumen $NH_3-N$ concentration increased with the increase in grass level and ranges from 8-46 mg/l. The rumen pH and the rate and extent of DM degradability of straw were not affeceted by different rumen environments created by different levels of grass inclusion. At 48 h, straw DM degradability were 42, 44, 44 and 43% respectively for 0, 2, 4 and 6 kg grass supplementation daily. The whole gut digestibilities of DM, OM and ADF increased significantly (p < 0.05) only at 6 kg level daily. The microbial N yield was not affected by the levels of grass supplemented. The mean microbial N yield was 10 (SD 3.7) g/kg DOM apparently fermented in the rumen. The estimated minimum N loss and thus the maintenance requirement of tissue protein was 303 mg/kg $W^{0.75}/d$. All the animals lost live weight but 6 kg grass supplementation gave positive energy and N balances. Small amount of green grass supplementation is often recommended for optimization of rumen environment of a straw diet However, under the present experimental condition, no such beneficiary effect observed up to 6 kg (26% of DM intake) level of supplementation.