• 한국식품위생안전성학회지
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• 제13권1호
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• pp.1-5
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• 1998

본 연구는 E. coli O157:H7에 대한 LP system(lactoperoxidae/thiocyanate/hydrogen peroxide)의 항균효과를 측정하기 위해 수행되었다. 초기 접종수준($10^{2},\;10^{4},\;10^{7}cfu/ml$), LP의 농도 (10ppm, 20ppm, 30ppm), 배지종류 (TSB, UHT milk, raw milk), 배양온도 ($5^{\circ}C,\;10^{\circ}C,\;15^{\circ}C$) 등에 따라 E. coli O157:H7에 대한 항균효과를 측정, 비교한 결과, 초기 접종수준을 $10^2/ml$으로 하였을 때와 LP의 농도를 10ppm 및 $5^{\circ}C$ 배양에서 항균력이 가장 높게 나타났다.

• 한국식품위생안전성학회지
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• 제15권3호
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• pp.262-266
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• 2000

우유에 포함된 Salmonella enteritidis를 효과적으로 분리하는 방법을 찾고 이를 이용하여 우유속의 S. enteritidis의 량을 추정하는 방법을 개발하였다. 일정량의 S. enteritidis를 접종한 우유로부터 guanidine thiocyanate/phenol/chloroform을 이용하여 DNA를 추출한 후 중합효소반응으로 S. enteritidis 섬모항원 유전자를 선택적으로 검출함으로써 우유 1ml당 200 colony forming unit까지 검출이 가능하였고 전체 과정의 수행에 단지 5시간 정도 걸렸다. S. enteritidis 섬모항원 유전자를 cloning한 pGem-4-Sef B(-) DNA와 인위적으로 접종된 우유로부터 추출한 Salmonella DNA를 함께 중합효소반응으로 증폭한 후 제한효소로 잘라 전기영동을 행하여 band의 강도를 비교함으로써 Salmonella DNA copy수를 추정하는 것이 가능하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권4호
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• pp.517-524
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• 2011

The effect on sow milk of variable levels of cassava in lactating sow diets was analyzed in an attempt to explain the beneficial effects reported by producers of including cassava as a basal feed. Twenty crossbred lactating sows were randomly assigned to five dietary treatments. The treatments were: i) broken rice (BR) as the basal feed (BR100), ii) 50% of BR replaced with cassava chip meal (CCM) (CM50), iii) 75% of BR replaced with CCM (CM75), iv) CCM as the basal feed (CM100), and v) dried boiled cassava chips (CCB) as the basal feed (CB100). The hydrocyanide (HCN) content of CCB was reduced to be intermediate between HCN in the no cassava (BR100) and the 50% cassava (CB50) diets. Hydrocyanide was 0.54, 3.24, 4.41, 5.43 and 1.77 ppm in the BR100, CM50, CM75, CM100 and CB100 diets, respectively. Increasing cassava did not affect feed intake (p>0.05), but increased HCN intake (p<0.01). Milk composition was analyzed for protein, fat, lactose, solids not fat (SNF) and total solids (TS). Milk quality was analyzed for total microbes, coliform bacteria, thiocyanate ($SCN^-$), lactoperoxidase (LPO), and glutathione peroxidase (GPx) activity. At farrowing, sow milk composition was not affected by experimental diets (p>0.05), but milk $SCN^-$ increased as the intake of HCN increased in sows diets (p<0.01), $r^2$ = 0.96. At mid-lactation (day 14), milk composition was not affected (p>0.05). The milk quality levels of $SCN^-$ were 9.4, 10.3, 10.5, 11.6 and 9.1 ppm for the BR100, CM50, CM75, CM100 and CB100 diets, respectively (p = 0.01). The LPO contents were 16.41, 42.13, 51.42, 53.94 and 22.81 unit/L, respectively (p = 0.03). There was no GPx activity found in sow milk. When BR was replaced with cassava meal, total microbes and coliforms were reduced 78% and 87%, respectively, by the influences of HCN. The reported beneficial effects of cassava chip meal as a basal feed in lactating sow diets is manifested by improved performance of suckling pigs. This is due to beneficial, non-toxic levels of HCN in the diets. Besides passing HCN to suckling pigs in the form of $SCN^-$, sow milk may also benefit suckling pigs with the observed (day 14) increase in lactoperoxidase content and reduction in coliform bacteria.

• Asian-Australasian Journal of Animal Sciences
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• 제13권5호
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• pp.600-604
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• 2000

Exp. I, the study was conducted to examine the supplementation levels of cassava hay (CH) in dairy cows. Six multiparous Holstein-Friesian crossbreds were paired and randomly assigned in a change-over design to receive three levels of CH supplement at 0, 0.8 and 1.7 kg DM/hd/d. Concentrate was supplemented at the same level (1:2; concentrate:milk yield) while urea-treated (5%) rice straw was offered on ad libitum basis. The results revealed that supplementation of CH could significantly reduce concentrate use resulting in similar milk yield (12.5, 12.12 and 12.6 kg/hd/d) and significantly enhanced 3.5% FCM (14.21, 15.70, 14.9 kg/d, respectively). Moreover, CH supplementation significantly increased milk fat and milk protein percentages especially at 1.70 kg/hd/d. Concentrate use could be significantly reduced by 27% at 1.7 kg/hd/d CH supplementation. Exp. II, supplementation of cassava hay to replace concentrate use was studied in lactating-Holstein Friesian crossbreds grazed on Ruzi grass. Six multiparous cows in mid-lactating periods were paired and randomly assiged according to a change-over-design to receive three dietary treatments, $T_1=0kg$ cassava hay (CH) in 1:2 concentrate supplementation (CS) to milk yield (MY), $T_2=1.0kg$ DM CH/hd/d in 1:3 CS to MY, $T_3=1.7kg$ DM CH/hd/d in 1:4 CS to MY, respectively. The results were found that milk yield were similar among treatments while protein, lactose and solids-not-fat percentages were highest (p<0.05) in cows receiving CH at 1.0 kgjhd/d. Most significant improvement from CH supplementation was the ability to reduce concentrate use by 42% which could provide a higher income for small-holder dairy farmers. In addition, milk thiocyanate was enhanced from 5.3 to 17.8 ppm (p<0.05) in the control and in the CH supplemented group (1.7 kg/hd/d), respectively. Moreover, CH supplementation could significantly reduce concentrate level for diary feeding thus resulted in more economical return. Cassava hay demonstrated as a potential and high-quality on-farm feed resource especially for dry season feeding in the tropics.

• Asian-Australasian Journal of Animal Sciences
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• 제16권3호
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• pp.463-472
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• 2003

Cassava (Manihot esculenta, Crantz), an annual tropical tuber crop, was nutritionally evaluated as a foliage for ruminants, especially dairy cattle. Cultivation of cassava biomass to produce hay is based on a first harvest of the foliage at three months after planting, followed every two months thereafter until one year. Inter-cropping of leguminous fodder as food-feed between rows of cassava, such as Leucaena leucocephala or cowpea (Vigna unculata), enriches soil fertility and provides additional fodder. Cassava hay contained 20 to 25% crude protein in the dry matter with good profile of amino acids. Feeding trials with cattle revealed high levels of DM intake (3.2% of BW) and high DM digestibility (71%). The hay contains tannin-protein complexes which could act as rumen by - pass protein for digestion in the small intestine. As cassava hay contains condensed tannins, it could have subsequent impact on changing rumen ecology particularly changing rumen microbes population. Therefore, supplementation with cassava hay at 1-2 kg/hd/d to dairy cattle could markedly reduce concentrate requirements, and increase milk yield and composition. Moreover, cassava hay supplementation in dairy cattle could increase milk thiocyanate which could possibly enhance milk quality and milk storage, especially in small holder-dairy farming. Condensed tannins contained in cassava hay have also been shown to potentially reduce gastrointestinal nematodes in ruminants and therefore could act as an anthelmintic agent. Cassava hay is therefore an excellent multi-nutrient source for animals, especially for dairy cattle during the long dry season, and has the potential to increase the productivity and profitability of sustainable livestock production systems in the tropics.

• Asian-Australasian Journal of Animal Sciences
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• 제22권10호
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• pp.1366-1376
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• 2009

Effect of sulfur (S) on utilization efficiency of fresh cassava foliage and cassava hay in dairy cows was evaluated using thirty-two $1^{st}-2^{nd}$ lactation Holstein-Friesian crossbred dairy cows. The experimental treatment was a 2${\times}$2 factorial arrangement in a randomized complete block design (RCBD) using two roughages (rice straw+fresh cassava foliage (FCF) and rice straw+cassava hay (CH)) and two elemental sulfur (S) levels (0.15 and 0.4% S of dry matter (DM)), respectively. Four dietary treatments (FCF+0.15, FCF+0.4, CH+0.15 and CH+0.4) were offered ad libitum in the form of a total mixed ration (TMR) with concentrate to roughage (chopped rice straw+chopped cassava foliage) ratio at 60:40. Fresh cassava foliage or cassava hay resulted in similar dry mater intake, rumen ecology parameters, total tract digestibility, blood chemistry, milk production and composition. However, HCN intake, blood and milk thiocyanate concentration were significantly higher (p<0.01) in cows fed fresh cassava foliage with no sign of potential toxicity. Dry matter intake, body weight changes, molar percentage of propionate in rumen, neutral detergent fiber (NDF) digestibility and nitrogen (N) retention of cows tended to be increased while DM digestibility (65.6, 72.7, 68.6 and 72.1% of total DM intake for the respective treatments), rumen bacteria population (1.4, 1.7, 1.6 and $1.7{\times}10^{11}$ cell/ml for respective treatments), fungal zoospore population (0.4, 0.6, 0.4 and $0.5{\times}10^{6}$ cell/ml for respective treatments), urinary allantoin (25.3, 28.0, 26.3 and 27.6 g/d for respective treatments), microbial N yield (136.0, 154.6, 142.8 and 151.3 g N/d for respective treatments) and milk protein content (3.4, 3.5, 3.2 and 3.5% for respective treatments) were significantly (p<0.05) higher in cows fed on supplemented sulfur at 0.4% of DM in comparison with 0.15% S-supplemented diets. Based on these results, it is concluded that cassava foliage could be used as a portion of roughage for dairy cows and supplementation of S would be nutritionally beneficial.