苎麻纤饲双收联合收获机的设计

该研究是针对苎麻麻秆和麻叶收获而设计的苎麻纤维、饲料双收联合收获机,设计了两套收割、输送、加工机构,构成纤维和饲料联合收获系统,同时完成苎麻纤维和饲料的收获,并完成麻骨、麻屑还田。该机是一种先进的农业机械设备,可以同时分别收割麻秆和麻叶,极大提高了苎麻收获生产效率、苎麻综合利用率和麻农经济效益,并减少环境污染。

苎麻新品种湘饲纤兼用苎1号选育

湘饲纤兼用苎1号是从地方品种咸丰大叶绿的自然变异单株中系统选育的新品种,既可以作为饲用苎麻栽培也可以作为常规纤维用苎麻栽培。2年5点饲用区域试验结果显示:鲜产量为123148.9~138624.7kg/hm^2,平均鲜产量131936.9kg/hm^2,比对照增产17.15%~20.34%,且丰产稳产性好;粗蛋白含量在22.5%,优于对照,粗纤维含量18.5%、粗脂肪含量6.5%、灰分含量13.6%、钙含量3.6%,均低于对照,磷含量0.4%左右,与对照无差异。纤维用区域试验结果显示:平均纤维产量2599.5kg/hm2,比对照平均值低5.2%左右;生产试验平均纤维产量为2676kg/hm2,减产6.5%以内;平均纤维支数2394.8支,比对照湘苎3号和中苎1号分别提高15.22%、22.06%。表明湘饲纤兼用苎1号是一个高产优质的饲纤兼用苎麻新品种。

Improvement of Cellulase Producing Capacity of Aspergillus niger by Ultraviolet Mutation

[Objective] The research aimed to breed the high-yield production strain of cellulase.[Method] Aspergillus niger was used as the starting strain,and a high-yield production strain of cellulase was selected after UV mutation treatment.[Result] Under the suitable condition,the strain 2（15） with the highest CMC production capacity was selected,which nearly increased 50% than that of the starting strain.[Conclusion] The research provided the foundation for its appliation in the feed production in the future.

Comparative Utilization of Different Fibre Feedstuffs by Weaning/Growing Pigs in the Tropics

This study was conducted to investigate the effect of feeding different fibre feedstuffs on the performance, nutrient utilization and economics of production of weaning/growing pigs. Five fibre feedstuffs--palm kernel cake （PKC）, wheat offal （WO）, corn bran （CB）, rice bran （RB） and brewers＇ dried grain （BDG） were used at 25% in each of the five experimental diets that were formulated in this study. Twenty weaner pigs （12.75 ± 0.6 kg） were used for the growth study while 15 pigs （14.95 ± 0.57 kg） were used for the digestibility study. The design of the experiment was completely randomized. The results of the study showed that the performance of the experimental animals were significantly influenced （P 〈 0.05） by the dietary treatments. The apparent digestibility of the crude protein, crude fiber and ether extract showed significant differences （P 〈 0.05） while there was no significant difference （P 〉 0.05） in the apparent digestibility of their dry matter, ash and nitrogen free extract. The diet that contained WO had the best growth response and apparent nutrient digestibility. Results of economics of production also showed that diet with WO gave the best （P 〈 0.05） value in feed cost/＇kg gain and net profit/animal. It can be concluded from this study that although all the animals fed the different fibre feedstuffs performed satisfactorily on all the parameters monitored, but for optimum growth, apparent nutrients digestibility and economics of production. WO should be used as a fibre feedstuff in the diets of weaning/growing pigs in the tropics.

Environmental Impacts of Feeding High-fiber Diet to Pigs

The concentration of volatile fatty acids （VFA） determined from a previous study was used to determine the concentration of carbon dioxide （CO2） and methane （CH4） in pig digesta using the model developed for ruminant animals. Digesta from the stomach, cecum and colon of pigs （n = 3 dietl） were used for the determination of VFA. The pigs were fed either a low fiber diet （LFD; 8.3% aNDF） as control, or one of the high-fiber diets （HFD, 22.4% aNDF; D1, D2 and D3） containing 1：2, 1：1 and 2：1, oats to barley ratios, respectively. Results indicated that the concentrations of CO2 and CH4 in pigs fed HFD were, on the average, 25.8 and 24.2%, respectively lower （P 〈 0.05） than pigs fed LFD. Pigs fed the highest oat to barley ratio also showed higher （P 〈 0.05） levels of CO2, （8.3%） and CH4 （5.1%）, compared to the average of the two lower ratios （CO2, 5.3% and CH4, 3.3%）. Molar proportions of VFA, CO2 and CH4 in the gut were in the order of VFA 〉 CO2 〉 CH4, at 53.0%, 28.6% and 18.4%, respectively, and CO2 and CH4 combined represented 47% of total gas.

Frequency of Occupation with Different Objects by Growing Rabbits under Various Conditions

The investigation was carried out with altogether 332 growing rabbits （ZIKA） in six rounds of 8 weeks duration respectively （R1-R6） with the following occupational objects： wooden gnawing stick （WGS）, plastic gnawing stick （PGS） and two iron chains connected by a horizontal stick （ICS）, wooden gnawing limb （WGL） and a horizontal iron chain （HIC）. The feeding system varied from pellet feeding ad libitum （in the first rounds, in the following rounds it decreased pro-rata whereas the proportion of the crude fibre feed （loose or pressed in blocks） increased appropriately） to crude fibre feeding ad libitum. The behavior ＂occupation with the tool＂ was infrared video recorded and continuously analyzed and summarized in hour-values per rabbit. The average frequency of occupation per rabbit and hour ranged from 0,13 to 2.19 concerning the rounds and between 0.12 and 1,30 concerning the tools. Altogether, it could be assumed that different occupational tools had an influence on the engaging behavior but the effect of the round which was affected by the feeding system was higher. The investigation showed that rabbits spent less time occupying with the tool when they were fed with an increasing percentage of crude fibre （less pellets） in the ration.

Effects of supplementary urea-minerals lick block on the kinetics of fibre digestion, nutrient digestibility and nitrogen utilization of low quality roughages

Three yearling lambs with a rumen cannula were used to investigate the effects of supplementation with an urea-minerals lick block （ULB） on the kinetics of ruminal fibre digestion, nutrient digestibility and nitrogen （N） utilization office straw （RS）, ammonia bicarbonate （AB）-treated RS （ABRS） and hay prepared from natural pasture. The digestibility of dry matter and organic matter of RS increased by 13.1% and 12.7% （P〈0.05） when the diet was supplemented with ULB, and approached to that of ABRS, indicating that the effect of ULB on digestibility of RS is similar to that of AB treatment. The digestibility of ABRS was slightly improved by the ULB feeding. Nitrogen retention was highest in lambs fed on ABRS alone, followed by hay with ULB, and was lowest in animals fed on RS with ULB. However, both the amount and proportion of N retention to N intake were enhanced by ULB supplementation to lambs fed on hay. The proportion of N retained to N digested decreased due to ULB supplementation to lambs fed on RS or ABRS. Supplementing ULB did not greatly influence the rumen degradation of either dry matter or crude protein in each of the three diets. RS and hay had similar values in the potential extent of digestion （PED） and digestion rate of PED （kd） of fibrous materials, but the discrete lag time for RS was lower than that for hay. The AB treatment significantly increased the PED （P〈0.05） and kd （P〈0.05） of RS. Neither the PED nor kd for RS and ABRS was influenced by ULB supplementation, but the kd for hay significantly increased due to ULB. The lag time for hay was also shortened by the ULB feeding. The ULB improved the digestion of fibre in the rumen of lambs fed on low quality roughage. It is inferred that while ULB is effective in increasing nutrient digestibility of low quality roughages by improving ruminal fibre digestion. A synchronized supply of N and energy to rumen microbes should be considered to improve the efficiency of N utilization when the basal diet is ammoniated straw.

Effect of TMF （Total Mixed Fiber） as Roughage Source on Rumen Fermentation in Lactating Dairy Cows

This experiment was conducted using by-products from agro-industry as dairy cows feed. Bagasse, pineapple peel, corn cob, corn stover and vinasses were used to produce TMF （total mixed fiber） for dairy cow feed. Fifteen multiparous Holstein Friesian dairy cows with an initial body weight of 417.88± 52.60 kg and 83.31 ± 26.47 DIM （days in milk） were randomly allocated to three treatments （TI = rice straw and 1 kg of vinasses; T2 = SCWS （sweet corn waste silage）; T3 = TMF （total mixed fiber）） under completely randomized design. The results showed that the chemical composition of TMF was in the normal range of pH and VFA （volatile fatty acids） on silage. However, cows fed TMF and SCWS tended to yield higher level of NH3-N. For volatile fatty acid in rumen fluid, acetate in group of cows fed rice straw with vinasse tended to be the highest. Moreover, propionate in cows fed TMF was found to be the highest among all treatments （P 〉 0.05）. In conclusion, the TMF can be used to feed dairy cow without affecting rumen parameter.

Gut Fermentation and Growth Performance of Pigs Fed High Fiber Diet

Ninety six pigs average weight 9.15 kg were used to study the effects of feeding diets containing multiple sources of dietary fiber （DF） on weight gain and concentration of fermentation products in the digestive tract. The experiment employed four diets and four pens diet1. Diets included a low fiber diet （LFD）, as control and three antibiotic free high-fiber diets （HFD） containing a 1：2, 1：1 or 2：1 oats：barley ratios. At the end of the 70 d feeding trial three pigs of comparable weight diefI were slaughtered. Digesta taken from the stomach, cecum and colon were used for the determination of volatile fatty acids （VFA）. Results indicated that inclusion of HFD increased （P 〈 0.05） feed intake but not weight gain. As revealed by the higher feed intake the nutritional value of HFD was approximately 88% of LFD. Also, as the amount of oats in the diet was increased, VFA concentration was also increased while isobutyrate decreased （P 〈 0.05）. Lower concentration of isobutyrate may indicate parallel reduction in other putatively toxic products of protein fermentation in the digestive tract. Thus, inclusion of multiple sources of fiber in the diet impacted feed intake and the products of gut fermentation in growing pigs.

Impacts of High Fiber Diet on Digestion and Absorption of Minerals in Growing Pigs

The study was conducted to investigate the effects of feeding high-fiber diet （HFD） on apparent total tract digestibility （ATTD） and absorption of minerals in growing pigs. Sixteen barrows averaging 16.39 kg were randomly assigned to one of four diets after metabolic crate assignment with individual pig serving as experimental unit. Diets include： a corn-soybean meal based low-fiber diet （LFD）, as the control （CON） and 3 HFD （D1, D2 and D3）, each containing 5% sugar beet pulps and a 1：2, 1：1 and 2：1 oats to barley ratios, respectively, replacing 47% of the corn in the diet. Diets were formulated to meet nutrient requirements, however, the fiber content of the LFD was substantially lower than the average of the HFD （8.38% vs. 22.40%）. Feed allowance was limited to 10% of average body weight and fed twice/d. The study period was divided into 10 d of adjustment and 5 d of feces collection. Data collected were analyzed using SAS, GLIMMIX procedure where animals were considered random effects, and minerals were fixed. Results of the study show that digestibility of Ca in pigs fed HFD was lower （P 〈 0.05） than in pigs fed LFD. On the other hand, the apparent digestibility of P, K, Na, S and Zn in pigs fed D2 and D3 were higher （P 〈 0.05） than in pigs fed CON diet. It was also observed that digestibility of Ca, P, K, Na, S and Zn in pigs fed D1 were lower （P 〈 0.05） than in CON, D2 or D3 fed pigs. Therefore, it was concluded that while feeding HFD reduced availability of Ca, the availability of P, K, Na and S to pigs improved as the oat to barley ratio in the diet increased.