Veum T L, Saenz C A, Iannotti E L
Agricultural Experiment Station, Division of Animal Sciences
Agricultural Experiment Station, Division of Animal Sciences.
J Anim Sci. 2015 Jan;93(1):197-208. doi: 10.2527/jas.2014-8449.
The experimental objective was to evaluate swine methane digester effluent (SMDE) as a water and nutrient source for swine. The mesophilic methane digester was loaded daily with manure from finishing swine fed a corn-soybean meal diet. Dry diet was mixed with SMDE (3.7% DM) and fed twice daily in troughs. Tap water was provided and consumption measured. Barrows were group fed (3 pigs/pen) and adapted to SMDE by increasing SMDE for 7 d, with the full amount fed from d 8 to the end of the feeding phase (d 21, 14, 23, or 37 for Exp. 1 to 4, respectively). Blood samples were collected on d 0, 10, 21, and 31 to determine plasma concentrations of glucose and plasma urea N (PUN). Barrows were placed in individual metabolism cages for a 5-d acclimation and a 5-d fecal and urine collection to determine apparent N and energy utilization. For Exp. 1, 18 pigs averaging 75 kg BW were allotted to diets with 0, 48.6, or 63.7% SMDE, as-fed basis. For Exp. 2 and 3, 12 pigs/experiment averaged 117 and 70 kg, respectively, and were allotted to diets with 0 or 63.7% SMDE, as-fed basis. At the end of Exp. 2 and 3, pigs were sacrificed and liver samples were collected to determine urea cycle enzyme activity, and loin was saved for taste panel evaluation. For Exp. 4, pigs averaged 40 kg and were allotted to diets with 0 or 57.5% SMDE, as-fed basis. The ADFI, ADG, and G:F of finishing swine (Exp. 1 to 3) were not reduced by feeding diets containing 63.7% SMDE (as-fed basis), whereas ADG and G:F of growing swine (Exp. 4) were reduced (P < 0.01) by feeding a diet containing 57.5% SMDE. Pigs fed diets containing SMDE consumed 31 to 56% less (P < 0.05) water and had greater (P < 0.01) PUN concentrations than pigs fed control diets. Pigs fed diets containing SMDE excreted more (g, P < 0.05) fecal N and absorbed and retained less N (%; P < 0.01) and energy (DE and ME) than pigs fed control diets. Treatment had no effect on urea cycle enzyme activity. In conclusion, finishing swine adapted to diets containing 63.7% SMDE (as-fed basis) based on growth performance, whereas growing swine did not adapt to a diet containing 57.5% SMDE because of the large content of nonprotein N in SMDE. Recycling SMDE to swine greatly reduced fresh water consumption, whereas the protein and energy values of SMDE were approximately 0 for swine. Therefore, SMDE is more appropriately recycled as a source of water and N for ruminant nutrition or crop production.
实验目的是评估猪沼气池废水（SMDE）作为猪的水和营养源的可行性。中温沼气池每天装入来自饲喂玉米 - 豆粕日粮的育肥猪的粪便。将干日粮与SMDE（干物质含量3.7%）混合，每天在食槽中饲喂两次。提供自来水并测量饮水量。将公猪分组饲养（每栏3头猪），通过在7天内逐渐增加SMDE的量使其适应SMDE，从第8天开始饲喂全量直至饲养期结束（实验1至4分别为第21天、14天、23天或37天）。在第0天、10天、21天和31天采集血样，以测定血浆葡萄糖浓度和血浆尿素氮（PUN）。将公猪置于个体代谢笼中进行5天的适应期，并进行5天的粪便和尿液收集，以测定表观氮和能量利用率。对于实验1，将18头平均体重75千克的猪分配到按饲喂基础计含0%、48.6%或63.7% SMDE的日粮组。对于实验2和3，每个实验12头猪，平均体重分别为117千克和70千克，分配到按饲喂基础计含0%或63.7% SMDE的日粮组。在实验2和3结束时，宰杀猪并采集肝脏样本以测定尿素循环酶活性，保留腰肉用于口感评定。对于实验4，猪平均体重40千克，分配到按饲喂基础计含0%或57.5% SMDE的日粮组。育肥猪（实验1至3）采食含63.7% SMDE（按饲喂基础计）的日粮时，其平均日采食量（ADFI）、平均日增重（ADG）和料重比（G:F）并未降低，而生长猪（实验4）采食含57.5% SMDE的日粮时，其ADG和G:F降低（P < 0.01）。采食含SMDE日粮的猪饮水量比采食对照日粮的猪少31%至56%（P < 0.05），且PUN浓度更高（P < 0.01）。采食含SMDE日粮的猪排出的粪便氮更多（克，P < 0.05），与采食对照日粮的猪相比，吸收和保留的氮（%，P < 0.01）和能量（消化能和代谢能）更少。处理对尿素循环酶活性无影响。总之，基于生长性能，育肥猪能适应采食含63.7% SMDE（按饲喂基础计）的日粮，而生长猪由于SMDE中非蛋白氮含量高，不能适应含57.5% SMDE的日粮。将SMDE循环用于猪可大幅减少新鲜水的消耗，而SMDE对猪的蛋白质和能量价值约为零。因此，SMDE更适合作为反刍动物营养或作物生产的水和氮源进行循环利用。
