在试验1中，148头猪只（初始体重18.6 kg）被单独放在代谢笼里；试验采用2 × 4因子评估2个不同水平的微生物植酸酶（0或500 单位/kg）×4种谷物来源（玉米，高赖氨酸、红或白高粱）。与未添加植酸酶相比，添加植酸酶改善了P的STTD（P < 0.05）；但在不同的谷物组间无影响。试验2中，三种高粱组和玉米组之间的DE和ME无差别。
试验3中，选用10头回肠末端安装瘘管的生长猪只（初始体重25.9 kg）进行试验；与高粱组相比，玉米组回肠可消化Lys、Met、Thr和Val显著提高（P < 0.05），但各高粱组间无差异。
在试验5中，处理组分别为：玉米基础日粮、常规高粱（红白高粱混合）基础日粮和4种高赖氨酸高粱日粮（增加了饲料级AA，替代SBM）。与其他日粮相比，饲喂提供最多饲料级AA的高赖氨酸高粱组猪只的饲料转化率G：F最低（P < 0.05）；随着高赖氨酸高粱和饲料级AA的增加，平均日增重（ADG）、终体重（线性，P < 0.10）和G：F（线性，P < 0.01）降低。
Nutritional evaluation of different varieties of sorghum and the effects on nursery pig growth performance
Five experiments were conducted to determine the standardized total tract digestibility (STTD) of P, digestible energy (DE), metabolizable energy (ME), and standardized ileal digestibility (SID) of amino acids (AA) in three sorghum varieties compared with corn and to determine the effects of sorghum varieties on nursery pig growth. In exp. 1, 48 barrows (initially 18.6 kg) were housed individually in metabolism crates. Treatments were arranged in a 2 × 4 factorial evaluating two levels of microbial phytase (0 or 500 units/kg) and four grain sources (corn, high-lysine, red, or white sorghum). Added phytase improved (P < 0.05) STTD of P in all ingredients, but was not different among the grains. In exp. 2, the DE and ME in the three sorghum varieties were not different from corn. In exp. 3, 10 growing barrows (initially 25.9 kg) with a T-cannula in the terminal ileum were used. Standardized ileal digestible Lys, Met, Thr, and Val were greater (P < 0.05) in corn than in the sorghum-based diets with no differences among the sorghum varieties. In exp. 4, 160 pigs (initially 6.3 kg) were randomly allotted to one of four dietary treatments with five pigs per pen and eight replicate pens per treatment in a 20-d experiment. Dietary treatments included corn or the three sorghum varieties, where the varieties of sorghum replaced corn on an SID Lys basis. No differences among treatments were observed in any growth performance parameters. In exp. 5, treatments consisted of a corn-based diet, a diet based on conventional sorghum (a mixture of red and white sorghum), and four diets with high-lysine sorghum containing increasing amounts of feed-grade AA, replacing soybean meal. Overall, pigs fed the high-lysine sorghum diet with the greatest amount of added feed-grade AA had the poorest gain:feed ratio (G:F; P < 0.05) compared with pigs fed all the other experimental diets. Within those fed the high-lysine sorghum and feed-grade AA, average daily gain, final body weight (linear, P < 0.10), and G:F (linear, P < 0.01) decreased as feed-grade AA increased. In summary, no differences in STTD of P or in DE and ME were observed among the grain sources. The SID AA values for the three sorghum varieties were not different; however, they were all lower than for corn. These results indicate that these varieties of sorghum can successfully replace corn in nursery pig diets if diets are formulated to account for differences in AA digestibility.