• 제목/요약/키워드: Nitrogen and Energy Utilization

검색결과 166건 처리시간 0.031초

Effects of different dietary ratio of metabolizable glucose and metabolizable protein on growth performance, rumen fermentation, blood biochemical indices and ruminal microbiota of 8 to 10-month-old dairy heifers

  • Sun, Jie;Xu, Jinhao;Ge, Rufang;Wang, Mengzhi;Yu, Lihuai;Wang, Hongrong
    • Asian-Australasian Journal of Animal Sciences
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    • 제31권8호
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    • pp.1205-1212
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    • 2018
  • Objective: The aim of this experiment was to evaluate the effects of different dietary ratio of metabolizable glucose (MG) to metabolizable protein (MP) on growth performance, blood metabolites, rumen fermentation parameters and the ruminal microbial community of 8 to 10-month-old heifers. Methods: A total of 24 Holstein heifers weighing an average of 282.90 kg (8 month of age) were randomly assigned to four groups of six. The heifers were fed one of four diets of different dietary MG/MP (0.97, 1.07, 1.13, and 1.26). Results: The results showed that the ratio of MG/MP affected the growth performance, blood metabolites, rumen fermentation parameters and the ruminal microbial community of heifers. The average daily gain of heifers was enhanced by increasing the ratio of MG/MP (p<0.05). The concentration of blood urea nitrogen, cholesterol, and low density lipoprotein cholesterol as well as the concentration of total volatile fatty acid in the rumen fluid of heifers decreased with the improvement in the ratio of dietary MG/MP (p<0.05). However, the relative amount of Ruminococcus albus and Butyrivibrio fibrisolvens in the rumen of heifers was increased significantly (p<0.05) when the dietary MG/MP increased. At the same time, with the improvement in dietary MG/MP, the amount of Fibrobacter succinogenes increased (p = 0.08). Conclusion: A diet with an optimal ratio (1.13) of MG/MP was beneficial for the improvement of growth, rumen fermentation, dietary protein and energy utilization of 8 to 10-month-old dairy heifers in this experiment.

러시안 컴프리와 케일의 급여(給與)가 병아리의 성장률(成長率), 영양소(營養素) 이용률(利用率) 및 혈청(血淸) Cholesterol 함량(含量)에 미치는 영향(影響) (Effects of Supplementing Russian Comfrey and Kale on the Growth Rate, Nutrients Utilizability and Serum Cholesterol of Chicks)

  • 한인규;모수미;김규일
    • Journal of Nutrition and Health
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    • 제2권2호
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    • pp.71-78
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    • 1969
  • This experiment was conducted for 4 weeks to compare the feeding values of dried meal of Russian Comfrey and Kale as green feeds with Acacia leaf meal and Ladino clover meal, and to investigate the effects of feeding these on the total cholesterol in blood serum and liver fat content. Seventy-five male chicks of Single Comb White Leghorn were allotted into 5 treatments. Fifteen birds in each treatment were received Russian Comfrey meal, Kale meal, Acasia leaf meal, Ladino clover meal or no dried meal, respectively. The results obtained are summarized as follows: 1. No significant differences were recognized between the treatments and control in the growth rate, feed consumption, feed efficiency, utilization of nutrients, nitrogen retention and metabolizable energy value. 2. Carotene content in Russian Comfrey and Kale has been decreased as the growing stage advanced, and the leaves of both vegetable contained significantly (p<0.01) more carotene than that in stems. Vitamin C content of leaves was also signifcantly (p<0.01) higher than that in stems, however, vitamin C content has been increased as the growing stage advanced. 3. Toltal cholesterol content in blood serum of the chickens fed the Acacia leaf meal or Russian Comfrey meal was significantly (p<0.05) lower than Ladino clover meal fed group or those received no green feeds. Kale seems to decrease cholesterol content a little. Above results indicated that Acacia leaf and Russian Comfrey might contain certain substances that would depressing the cholesterol content. 4. No significant differences in the liver fat were discovered among the treatment but it was observed that liver fat was decreased as the cholesterol content increased.

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Effect of Feed Protein Source on Digestion and Wool Production in Angora Rabbit

  • Bhatt, R.S.;Sawal, R.K.;Mahajan, A.
    • Asian-Australasian Journal of Animal Sciences
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    • 제12권7호
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    • pp.1075-1079
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    • 1999
  • Adult German cross $(German{\times}British{\times}Russian)$ angora rabbits (one year age), 32 in number were divided randomly into four groups $(T_1-T_4)$ with equal sex ratio and fed diets containing $T_1$ groundnut cake (GNC); $T_3$, soyaflakes (SF); $T_4$, sunflower cake (SFC) and $T_2$, a mixture of all the three cakes along with green forage as roughage for a period of 9 months. Nine per cent protein was added from each protein source. Fibre level was maintained by adjusting the level of rice phak in the diets. The diets were iso-nitrogenous and contained similar level of fibre. DMI through roughage was not affected due to source of protein in the diet, however, DMI through concentrate was higher $(p{\leq}0.05)$ with SFC diet, which resulted in higher total feed intake in the group $(T_4)$. Body weights increased up to second shearing, thereafter it decreased due to summer depression. Diet containing soyaflakes sustained higher wool yield whereas, it was lowest $(p{\leq}0.05)$ on SFC diet. Wool attributes (staple length, medullation, fibre diameter) were not affected due to source of protein in the diet. Digestibility of fibre and its fractions (ADF, cellulose, hemicellulose) decreased $(p{\leq}0.05)$ with incorporation of SFC in the diets. Balance of calcium was lowest whereas, that of nitrogen was highest with SFC diet $(T_4)$. Biological value of N and net protein utilization was better when different protein sources were mixed together $(T_2)$. Protein quality of soyaflakes proved better for wool production followed by groundnut cake and mixture of three protein sources. Sunflower cake alone or in combination decreased wool production which may be checked by supplementation of amino acids and energy.

목재 펠릿 난로와 보일러 사용에 의한 대기오염물질과 블랙카본의 배출 특성 (Emission Characteristics of Air Pollutants and Black Carbon from Wood-pellet Stove and Boiler)

  • 박성규;유근정;김대근;김동영;장영기;전의찬
    • 한국기후변화학회지
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    • 제6권1호
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    • pp.41-47
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    • 2015
  • This study was carried out simulating domestic utilization conditions of a wood pellet stove and a wood pellet boiler in order to determine emission factors (EFs) of macro-pollutants, i.e., carbon monoxide, nitrogen oxides, sulfur oxides, ammonia, particulate matters (total suspended particulate, $PM_{10}$, $PM_{2.5}$, black carbon) and trace pollutants (i.e., ten different volatile organic compounds). The composite pollutants EFs for the pellet stove were: for TSP 4.58 g/kg, for $PM_{10}$ 3.35 g/kg, for $PM_{2.5}$ 2.48 g/kg, CO 119.23 g/kg, NO 14.40 g/kg, $SO_2$ 0.17 g/kg, TVOC 37.73 g/kg, $NH_3$ 0.02 g/kg and emissions were similar to the pellet boiler appliance: for TSP 4.73 g/kg, for $PM_{10}$ 3.41 g/kg, for $PM_{2.5}$ 2.63 g/kg, CO 161.51 g/kg, NO 13.67 g/kg, $SO_2$ 0.19 g/kg, TVOC 45.22 g/kg, $NH_3$ 0.02 g/kg.

Pellet사료(飼料)의 급여(給與)가 병아리의 대사(代謝)에너지와 질소축적(窒素蓄積)에 미치는 영향(影響) (Studies on the Effect of Feeding Pelleted Diets on Energy Metabolism and Nitrogen Retention in Growing Chickens)

  • 박창식;권순기;민태혁
    • 농업과학연구
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    • 제10권2호
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    • pp.206-211
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    • 1983
  • 한국(韓國)에서 사육(飼育)되고 있는 닭의 육용종(肉用種)과 난용종(卵用種)의 초생추(初生雛 )를 공시동물(供試動物)로 하여 사료(飼料)의 조성분(組成分)과 배합률(配合率)이 동일(同一)한 pellet사료(飼料)와 all-mash사료(飼料)를 급여(給與)하여 사료섭취량(飼料攝取量)과 증체량(增體量) 및 대사(代謝)에너지와 질소축적률(窒素蓄積率)의 차이(差異)를 측정(測定)하여 pellet사료(飼料)를 급여(給與)함으로써 사료(飼料)의 효율적(效率的) 이용(利用)을 기대(期待)한 본(本) 시험(試驗)의 결과(結果)는 다음과 같다. 1. 각(各) 주별(週別) 1 수당(首當) 평균(平均) 증체량(增體量)은 5주령(週令)부터 pellet구(區)가 높아졌는데, 9주령(週令)에서 평균(平均) 1 수당(首當) 체중(體重)은 Hubbard의 pellet구(區)가 2,702g이었고 all-mash구(區)는 2,571g으로 pellet구(區)가 131g 더 증체(增體)되었고, Hy-line을 pellet구(區)와 all-mash구(區)가 각각(各各) 812g과 777g으로 전자(前者)가 35g 더 증체(增體)되어 pellet 사료(飼料)를 급여(給與)한 구(區)가 증체율(增體率)이 높은 결과(結果)였다. 2. 9주간(週間)의 1 수당(首當) 사료섭취총량(飼料攝取總量)은 pellet구(區)가 all-mash구(區)에 비(比)하여 육용종(肉用種)은 69g, 난용종(卵用種)은 75g을 더 섭취(攝取)하였다. 이 사료섭취량(飼料攝取量)에 의(依)해서 9주령(週令)까지의 사료효율(飼料效率)을 보면 육용종(肉用種)의 pellet구(區)는 0.38, all-mash구(區)는 0.36이며, 난용종(卵用種)은 0.26과 0.25로 pellet구(區)가 약간(若干) 높았다. 음수량(飮水量)은 난용종(卵用種)에 있어서 pellet구(區)가 all-mash구(區)보다 많았다. 3. 분뇨(糞尿)의 배설량(排泄量)도 사료섭취량(飼料攝取量)과 같이 pellet구(區)가 약간(若干) 많았고 질소(窒素)의 섭취율(攝取率)은 육용종(肉用種)이 57~67%였으며 난용종(卵用種)은 65~73% 였는데 두 품종(品種)이 다 같이 pellet구(區)가 all-mash구(區)보다 1~4% 정도(程度) 개선(改善)되는 것을 인정(認定)하였다. 4. 대사(代謝)에너지의 효율(效率)은 8주령(週令)에서 육용종(肉用種)이 73.4~74.3%였고 난용종(卵用種)은 82.8~83.8%로서 pellet구(區)가 1%정도(程度) 높았다. 5. 생산(生産)에너지를 호흡시험(呼吸試驗)에 의(依)해서 측정(測定)한 결과(結果)는 대사체중당(代謝體重當) 발생열량(發生熱量)이 pellet구(區)에서 94.1~102.6kcal였고 all-mash구(區)는 106.1~112.6kcal였으며 생산(生産)에너지의 효율(效率)도 41.3~48.9%와 39.0~45.8%로 pellet구(區)가 약(約) 2~3%정도(程度) 높은 것을 인정(認定)하였다. 6. 본(本) 시험(試驗)의 결과(結果)에 의(依)해서 사료(飼料)를 pelleting함으로써 얻을 수 있는 효과(效果)는 사료섭취량(飼料攝取量)과 증체량(增體量)이 증가(增加)되었으며 사료효율(飼料效率)도 높아지고 대사(代謝)에너지와 생산(生産)에너지의 이용율(利用率)도 높아지는 것을 인정(認定)하였다. 그러나 pellet사료(飼料)와 all-mash 사료(飼料)의 급여(給與)가 열량증가(熱量增加)의 차이(差異)에 어떤 mechanism으로 영향(影響)하는지는 앞으로 계속(繼續)해서 구명(究明)할 필요(必要)가 있다.

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열량 영앙소의 수준이 흰쥐의 단백질 평형과 체조성에 미치는 영향 (Effects of Varying the Concentration of Energy Yielding Nutrients on Nitrogen Balance and Body Composition of the Growing Rats)

  • 장유경;한인규
    • Journal of Nutrition and Health
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    • 제13권3호
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    • pp.117-125
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    • 1980
  • 섭취된 단백질이 성장하는 쥐의 체내에서 이용되는 효율을 알고, 지방 섭취량이 단백질 대사에 어떤 영향을 주는지 알기 위해서 생후 6주되고 평균 체중이 약 106g 정도되는 Sprague-Dawley 계 albino rat 숫컷 51마리를 사용하여 (3 마리는 개시시 도체분석에 사용하고, 48마리는 사양시험에 사용하였음) 시험 사료의 에너지 수준은 M.E.가(價)가 4000Kca1/kg으로 모두 같게 하되 단백질 공급 수준은 저단백질구(10%), 중단백질구(20%), 고단백질구(30%)로 하고, 지방 급여 수준은 각 단백질 수준마다 총 에너지의 20%(저지방구), 40%(고지방구)로 정하고 나머지 에너지는 전분과 포도당으로 보충한 6종의 사료처리구에 대한 사양시험, 대사시험 및 도체분석 시험을 실시했던바 얻어진 결과를 요약하면 다음과 같다. 1) 증체량은 사료의 단백질 수준을 증가시킬 경우 저지방구에서는 증가했으나 고지방구에서는 오히려 감소되있다. 사료 효율은 저지방구에서는 단백질 공급수준을 높일수록 증가되었으나 고지방구에서는 일정한 경향을 찾을 수 없었다. 단백질 효율에 있어서는 저단백질구의 그것이 높았는데 특히 저단백질 고지방구(LPHO)의 단백질 효율이 가장 높았으며 단백질 수준이 높아질수록 지방의 공급량에 관계없이 저하되었다. 2) 고형물, 단백질 총탄수화물의 소화율은 같은 수준의 단백질을 공급하는 경우 고지방구의 것보다 저지방구의 것이 높았으며, 단백질 급여 수준이 높을수록 고형물과 탄수화물의 소화율은 약간 감소되었으나, 단백질의 소화율은 오히려 약간 증가되었다. 지방의 소화율은 사료의 단백질이나 지방의 급여 수준에 큰 영향을 받지 않고 모두 높았다. 3) 질소 이용률에 있어서는 중단백질구(20%)인 경우 저지방구가 가장 높았으나, 고지방구는 가장 낮았다. 사료단백질 20%까지는 저지방 수준인 경우 질소이용률이 뚜렷하게 높은 것을 알 수 있었으나 고단백질구(30%)에서는 지방의 급여량에 따른 차이를 볼 수 없었다. 4) 에너지 섭취량은 사료의 단백질과 지방 수준에 따라서 영향을 받았다. 각 처리구별로 에너지의 대사율을 비교해 보면, 첫째로 사료의 단백질 수준이 높아질수록 에너지 대사율은 약간씩 낮아졌고, 둘째로 같은 단백질 수준에서는 저지방구의 에너지 이용률이 고지방구의 그것보다 훨씬 높았다. 5) 체성분은 시험 개시시 체조성에 미하여 체수분은 감소되었고 체단백질과 체지방은 모두 증가되었다. 단백질 공급 수준이 높아질수록 체수분은 높았고, 체단백질과 체지방은 모두 낮은 경향이 있었다. 단백질 수준이 같을 경우 고지방구의 체수분은 저지방의 그것보다 높았으며 체단백질과 체지방은 오히려 고지방구에서 낮은 경향을 보였다. 6) 이상에서 설명한 실험결과를 종합하여 볼 때 성장하는 흰쥐의 경우 단백질 20%, 지방 20%, 탄수화물 60%로 구성된 식이가 가장 이상적인 것으로 생각된다.

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Responses of Dairy Cows to Supplemental Highly Digestible Rumen Undegradable Protein and Rumen-protected Forms of Methionine

  • Sun, T.;Yu, X.;Li, S.L.;Dong, Y.X.;Zhang, H.T.
    • Asian-Australasian Journal of Animal Sciences
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    • 제22권5호
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    • pp.659-666
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    • 2009
  • Metabolizable protein (MP) supply and amino acid balance in the intestine were manipulated through selection of highly digestible rumen-undegradable protein (RUP) sources and protected methionine (Met) supplementation. Four ruminallycannulated, multiparous Holstein cows averaging 193${\pm}$13 days in milk were used in a 4${\times}$4 Latin square design to assess N utilization and milk production responses to changes in RUP level, post-ruminal RUP digestibility and protected Met supplementation. Treatments were A) 14.0% crude protein (CP), 8.0% rumen degradable protein (RDP) and 6.0% RUP of low intestinal digestibility (HiRUP-LoDRUP); B) 14.1% CP, 8.1% RDP and 6.0% RUP of high intestinal digestibility (HiRUP-HiDRUP); C) 13.1% CP, 7.9% RDP and 5.2% RUP of high intestinal digestibility (LoRUP-HiDRUP), and D) 13.1% CP, 7.9% RDP and 5.2% RUP of high intestinal digestibility plus rumen escape sources of Met (LoRUP-HiDRUP+Met). Experimental diets were formulated to have similar concentrations of RDP, net energy of lactation ($NE_L$), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium, phosphorus and ether extract using the NRC model (2001). Results showed that dry matter intake (DMI), production of milk fat and protein were similar among treatments. Milk production was similar for diet HiRUP-LoDRUP, HiRUP-HiDRUP and LoRUP-HiDRUP+Met, and significantly higher than diet LoRUP-HiDRUP. Milk fat and protein percentage were higher for cows receiving HiDRUP treatments, with the greatest increases in the diet LoRUP-HiDRUP+Met. There was no significant change in ruminal pH, $NH_3g-N$ and volatile fatty acid (VFA) concentration among all treatments. Apparent digestibility of dry matter (DM), CP, NDF and ADF and estimated bacterial CP synthesis were similar for all treatments. Nitrogen intakes, blood and milk urea-N concentrations were significantly higher for cows receiving HiRUP diets. Urine volume and total urinary N excretion were significantly lowered by LoRUP diets. Lowering dietary RUP level while supplementing the highly digestible RUP source with rumen escape sources of Met resulted in similar milk production, maximal milk fat and protein concentration and maximum N efficiency, indicating that post-ruminal digestibility of RUP and amino acid balance in the small intestine can be more important than total RUP supplementation.

Effect of Sodium Hydroxide plus Hydrogen Peroxide Treated Mustard (Brassica campestris) Straw Based Diets on Rumen Degradation Kinetics (In sacco), Fermentation Pattern and Nutrient Utilization in Sheep

  • Mishra, A.S.;Misra, A.K.;Tripathi, M.K.;Santra, A.;Prasad, R.;Jakhmola, R.C.
    • Asian-Australasian Journal of Animal Sciences
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    • 제17권3호
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    • pp.355-365
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    • 2004
  • Two experiments were conducted to determine the effect of alkaline hydrogen peroxide (AHP) treatment (1% NaOH+1.5% $H_2O_2$; 1 AHPMS, 2% NaOH+1.5% $H_2O_2$; 2AHPMS) on rate and extent of degradation of mustard straw (MS) in sacco in sheep, and its in vivo digestion and ruminal fermentation characteristics when fed to sheep with concentrate (200 g per sheep daily). The treatment of straw with 1 and 2% AHP increased its sodium content by 148 and 296% to that of untreated straw (UMS). There was significant decrease in NDF and hemicellulose contents of AHP treated straw and increase in cellulose and lignin contents. Phenolic acids like ferrulic, $\rho$-coumaric and o-coumaric significantly (p<0.001) reduced by AHP treatment of mustard straw. In first experiment the in sacco degradation of DM, OM and NDF was significantly (p<0.01) greater for 2 AHPMS than for UMS at all incubation periods. The disappearance of nutrient from 1 AHPMS and 2 AHPMS treated straws continue to increase up to 96 h whereas in UMS the peak disappearance was found at 48 h. By using the equation {(y=a+b) ($1-e^{-ct}$)} the degradation rates (c) for DM, OM, and NDF were significantly higher for UMS than AHP treated straws. Level of alkali (1 and 2%) had significant effect on degradation characteristics (a, b, c and $P_{0.05}$) of DM and NDF fraction of MS. However, the effect was not pronounced on OM fraction of MS. In feeding experiment, the intake of nutrients for DM, OM, cell wall constituents and energy was higher on 2 AHPMS, whereas no effect on the digestibility of these nutrients was observed. The apparent nitrogen retention was higher (p<0.05) both in 1 and 2 AHPMS groups. Water intake by animals was significantly increased due to AHP treated mustard straw feeding. Rumen liquor pH was higher in 2 AHPMS fed animals. The $NH_3-N$ of rumen liquor was not affected by feeding of AHP treated MS based diets. Total VFA concentration was significantly (p<0.01) higher in UMS fed group. The fractional out flow rate of DM was higher (p<0.05) in animals fed on 2 AHPMS diets compared to UMS and lAHPMS fed groups. The population of large holotrichs was higher (p<0.05) on AHP treated MS fed diets compared to UMS. The study indicated that treatment of mustard straw with AHP changed its chemical composition towards a better feed. The nutritive value of 2% AHP treated mustard straw was better in terms of dry matter intake and apparent nitrogen retention. The higher in sacco DM, OM and NDF disappearance however, was not confirmed by in vivo data in this study.

Growth Performance and Caecal Fermentation in Growing Rabbits Fed on Diets Containing Graded Levels of Mulberry (Morus alba) Leaves

  • Prasad, Rajendra;Misra, A.K.;Sankhyan, S.K.;Mishra, A.S.;Tripathi, M.K.;Karim, S.A.;Jakhmola, R.C.
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권9호
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    • pp.1309-1314
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    • 2003
  • Growth performance, nutrient digestibility and changes in caecal fermentation pattern was studied on four groups of 8 grower rabbits (soviet chinchilla) each, fed on diets containing 17 to 18% CP and $10.4-11.00MJ\;DE\;kg^{-1}$ feed. The complete diets contained mulberry leaves along with other feed ingredients at 0 (LH), 15 (ML15), 30 (ML30) and 45% (ML45) levels. In LH diet ground lucerne hay was added at 15% of the diet as roughage source. The diets were uniform in other nutritional parameters except the higher amount of hemicellulose (18.7 and 16.5%) in LH and ML15 diets. The performance of grower rabbits was better (p<0.05) on LH and ML15 diets in terms of twelve weeks weight (kg), total gain (g), average daily gain (ADG) and feed efficiency (%). Different levels of mulberry leaves in the diet did not influence the dry matter intake. Digestibility of nutrients for DM, OM, CP, NDF and energy was uniform in all the diets but the digestibility of CF, ADF and cellulose was higher (p<0.01) on ML15, ML30 and ML 45 diets. The hemicellulose digestibility was significantly higher (p<0.01) on LH (44.52%) and ML15 (48.00%) compared to ML30 (33.54%) and ML 45 (39.17%) diets. The nitrogen retention (% of intake) was higher (p<0.05) in LH and ML15 diets than ML30 and ML45 diets. The caecum weight as percent of intestine weight consistently increased (p<0.05) with increasing content of mulberry leaves in diets. Total nitrogen and $NH_3$-N was higher on LH and ML15 diets. It is concluded that incorporation of mulberry leaves can replace Lucerne hay in complete rabbit feed (15% in diet). Even at higher level i.e. 30 and 45% of the diet mulberry leaves based complete feed gave promising results.

Supplementing Maize or Soybean Hulls to Cattle Fed Rice Straw:Intake, Apparent Digestion, In situ Disappearance and Ruminal Dynamics

  • Von, Nguyen Tien;St. Louis, David G.;Orr, Adam I.;Rude, Brian J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제21권6호
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    • pp.807-817
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    • 2008
  • Steers with ad libitum access to rice straw were assigned to four diets to evaluate the effects of maize or soybean hull supplementation on intake, in vivo digestibility, ruminal pH, VFA, ammonia-nitrogen ($NH_3-N$) and in situ ruminal disappearance of feed nutrients by cattle consuming rice straw. Supplement treatments were: no supplement (RS); soybean meal at 0.127% BW (SBM); cracked maize at 0.415% BW plus 0.044% BW soybean meal (MAIZE); or soybean hulls at 0.415% BW plus 0.044% BW soybean meal (HULLS). The MAIZE and HULLS diets were formulated to provide approximately 4 MJ of $NE_m$ per kg of diet. Rice straw DMI was not affected (p = 0.34) by supplement. Apparent dry matter (DM) digestibility was greater (p<0.001) for MAIZE and HULLS (56.6 and 60.0%, respectively) than for steers consuming SBM or RS (51.8 and 44.4%, respectively). Apparent NDF digestibility was greater (p<0.0004) for HULLS than MAIZE (61.7 vs. 58.0%, respectively) and apparent ADF digestibility was greater (p<0.0008) for HULLS than MAIZE (61.1 vs. 49.2%, respectively). There was no difference in apparent hemicellulose digestibility (p = 0.43). Analysis of ruminal fluid collected 0, 2, 4, 6, and 8 h post-feeding revealed ammonia-nitrogen was greatest (p<0.05) for steers on SBM and HULLS diets at 2 h (24.08 and 22.57 mg/dl, respectively) and total volatile fatty acids was greatest (p<0.05) for HULLS at 4 h (230 mM/L). In situ disappearance, measured at 0, 2, 4, 6, 8, 16 and 24 h, indicated that SBM, MAIZE and HULLS tended to enhance the digestibility of DM and fiber components of rice straw. In situ disappearance of rice straw DM was greatest for SBM and/or HULLS from 4 to 24 h (p = 0.03). Rice straw NDF and ADF disappearance was enhanced by supplementation from 16 to 24 h (p<0.02). Rice straw DM, NDF and ADF disappearances at 24 h were similar for MAIZE and HULLS treatments. When feeding cattle rice straw diets, energy and protein-based supplements are essential. This study showed that fiber-based supplements are just as, if not more, effective as starch-based supplements in rice straw utilization. This study shows that soybean hulls, in spite of their high fiber content, are as efficient as maize for supplementing rice straw primarily because fiber in soybean hulls is highly digestible as shown by in vivo digestibility and in situ disappearance.