The effects of birth weight and estimated breeding value for protein deposition on nitrogen efficiency in growing pigs

The effects of birth weight (BiW; low BiW [LBW] vs. high BiW [HBW]) and estimated breeding value (EBV) for protein deposition (low EBV [LBV] vs. high EBV [HBV]) on N retention, N efficiency, and concentrations of metabolites in plasma and urine related to N efficiency in growing pigs were studied. At an age of 14 wk, 10 LBW–LBV (BiW: 1.07 ± 0.09 [SD] kg; EBV: −2.52 ± 3.97 g/d, compared with an average crossbred pig with a protein deposition of 165 g/d), 10 LBW–HBV (BiW: 1.02 ± 0.13 kg; EBV: 10.47 ± 4.26 g/d), 10 HBW–LBV (BiW: 1.80 ± 0.13 kg; EBV: −2.15 ± 2.28 g/d), and 10 HBW–HBV (BiW: 1.80 ± 0.15 kg; EBV: 11.18 ± 3.68 g/d) male growing pigs were allotted to the experiment. The pigs were individually housed in metabolism cages and were subjected to an N balance study in two sequential periods of 5 d, after an 11-d dietary adaptation period. Pigs were assigned to a protein adequate (A) or protein restricted (R, 70% of A) regime in a change-over design. Pigs were fed 2.8 times the energy requirements for maintenance. Nontargeted metabolomics analyses were performed in urine and blood plasma samples. The N retention (in g/d) was higher in the HBW than in the LBW pigs (P < 0.001). The N retention (in g/[kg metabolic body weight (BW^0.75) · d]) and N efficiency, however, were not affected by the BiW of the pigs. The N retention (P = 0.04) and N efficiency (P = 0.04) were higher in HBV than in LVB pigs on the A regime but were not affected by EBV in pigs on the R regime. Restricting the dietary protein supply with 30% decreased the N retention (P < 0.001) but increased the N efficiency (P = 0.003). Nontargeted metabolomics showed that a hexose, free amino acids (AA), and lysophosphatidylcholines were the most important metabolites in plasma for the discrimination between HBV and LBV pigs, whereas metabolites of microbial origin contributed to the discrimination between HBV and LBV pigs in urine. This study shows that BiW does not affect N efficiency in the later life of pigs. Nitrogen efficiency and N retention were higher in HBV than in LBV pigs on the A regime but similar in HBV and LBV pigs on the R regime. In precision feeding concepts aiming to further optimize protein and AA efficiency in pigs, the variation in EBV for protein deposition of pigs should be considered as a factor determining N retention, growth performance, and N efficiency.     

Comparison of Odor Emissions from Three Different Biosolids Applied to Forest Soil

The odor emissions from three types of biosolidsfrom King County, WA, were measured usingdilution-to-threshold olfactometry and mass spectralanalyses. This article describes thermal desorption andcryogenic GC/MS methods developed to characterizeodorant emissions from biosolids application to forestsoil. The major odorous compounds volatilized from twoanaerobically digested biosolids were ammonia anddimethyl disulfide, with lesser quantities of carbondisulfide, dimethyl sulfide, trimethyl amine, acetoneand methyl ethyl ketone. A third type of biosolidswas formed by centrifuge and drying one of the otherbiosolids at 190 °C. This dry biosolids producedmore odor and volatilized a more complex array ofvolatile compounds including: dimethyl disulfide,dimethyl sulfide, carbon disulfide, methylethyldisulfide, methane thiol, trimethyl amine, aceticacid, propionic acid, and butyric acid. Odor unitemissions were not found to correlate with microbialactivity, initial biosolids ammonium, organicnitrogen, and total sulfur. Variability in odoremission were explained by the number of odorouscompounds volatilized from each material, surface areaof biosolids and drying of the biosolids.     

Air-liquid partition coefficients of aroma volatiles in frozen sugar solutions

Static headspace gas chromatography was used to measure air-solution partition coefficients of homologous series of methyl ketones and ethyl esters in aqueous sugar solutions. The measurements were performed in a temperature range from 25 to -25 degrees C. A rather unexpected temperature dependence of the partition coefficients was observed at subzero temperatures; that is, partition coefficients were found to increase in the temperature interval from 0 to -10 degrees C. A simple model, based on the freeze concentration effect, is proposed to explain the observed temperature dependence.     

A review with some applications of statistical selection procedures for selecting the best variety

Summary Statistical selection procedures are discussed in general terms. Statistical selection procedures have been designed specifically to answer questions like Which treatment or variety can be considered to be the best?. In a certain sense statistical selection procedures are more realistic in answering such a question than the usual testing and multiple comparisons procedures. The statistical procedures of Bechhofer and Gupta are considered. Some practical applications are given. Finally, attention is paid to the relatively new combined procedure of Hsu (1981, 1984) and the procedures of Somerville (1985).     

Prediction of nutrient digestibility in grower-finisher pigs based on faecal microbiota composition

Microbiota play an important role in total tract nutrient digestion, especially when fibrous diets are fed to pigs. This study aimed to use metagenomics to predict faecal nutrient digestibility in grower-finisher pigs. The study design consisted of 160 three-way crossbreed grower-finisher pigs (80 female and 80 male) which were either fed a diet based on corn/soybean meal or a more fibrous diet based on wheat/barley/by-products. On the day before slaughter, faecal samples were collected and used to determine faecal digestibility of dry matter, ash, organic matter, crude protein, crude fat, crude fibre and non-starch polysaccharides. The faecal samples were also sequenced for the 16S hypervariable region of bacteria (V3/V4) to profile the faecal microbiome. With these data, we calculated the between-animal variation in faecal nutrient digestibility associated with variation in the faecal microbiome, that is the “microbiability”. The microbiability values were significantly greater than zero for dry matter, organic matter, crude protein, crude fibre and non-starch polysaccharides, ranging from 0.58 to 0.93, as well as for crude fat with a value of 0.37, but not significantly different from zero for ash. Using leave-one-out cross-validation, we estimated the accuracy of predicting digestibility values of individual pigs based on their faecal microbiota composition. The accuracies of prediction for crude fat and ash digestibility were virtually 0, and for the other nutrients, the accuracies ranged from 0.42 to 0.63. In conclusion, the faecal microbiota composition gave high microbiability values for faecal digestibility of dry matter, organic matter, crude protein, crude fibre and non-starch polysaccharides. The accuracies of prediction are relatively low if the interest is in precisely predicting faecal nutrient digestibility of individual pigs, but are promising from the perspective of ranking animals in a genetic selection context.     

Genetic analysis of resistance to <Emphasis Type="Italic">Fusarium</Emphasis> root rot in common bean

Fusarium root rot (FRR) is a major disease of common bean worldwide. Knowledge of the inheritance of resistance to FRR would be important in devising strategies to breed resistant varieties. Therefore, a 12 × 12 full diallel mating scheme with reciprocal crosses was performed to generate 132 F₁ progenies, which were then advanced to the F₃. The progenies were evaluated for resistance to FRR under green house conditions in Uganda. General combining ability (GCA) effects were highly significant (P ≤ 0.01) for disease scores. Specific combining ability effects were not significant (P > 0.05) in the F₁, but were highly significant (P < 0.01) in the F₃ generation. These results indicate that resistance to FRR was governed by genes with additive effects in combination with genes with non-additive effects. Reciprocal differences were also significant (P = 0.01) at F₁ and F₃, primarily reflecting a large influence of maternal effects in both these generations. In fact, susceptible parents did not differ significantly (P > 0.05) for disease scores when used as paternal parents in the F₃, but differed strongly as maternal parents (P = 0.0002). Generally, the progenies were distinctly more resistant when the resistant parent was used as the female in crosses, especially as observed in the F₃. The maternal effects were strong in the F₃ generation, suggesting a complex form of cytoplasmic–genetic interaction. The non-maternal reciprocal effects in the F₃ were significant (P < 0.05) in both the resistant × resistant diallel, and in the resistant × susceptible crosses. Mid-parent heterosis (MPH) occurred in most crosses, with average heterosis approximately equal in each of the three generations, indicating that epistasis was probably more influential than dominance of individual genes. Gene-number formulas indicated that several genes were involved in resistant × susceptible crosses. Among resistant × resistant crosses, many produced continuous distributions of F₁ progeny scores, suggesting polygenic inheritance, while bi-modal distributions were characteristic of the F₃ distributions, and fit expected ratios for two or three loci segregating in each cross. Dominant forms of epistasis favoring resistance were strongly indicated. Parent–offspring heritability estimates were moderate. Overall, the results indicate that resistant parents contain a number of different resistance genes that can be combined with the expectation of producing strong and durable resistance. The lines MLB-49-89A, MLB-48-89, RWR719 and Vuninkingi, with large and negative GCA effects, contributed high levels of resistance in crosses and would be recommended for use in breeding programs.     

森林公园道路景观林的改造配置模式——以老山森林公园为例

道路景观林是山林景观的窗口和向导,道路景观林的建设是森林林相改造的重要内容。以南京市老山森林公园为例,探讨道路景观林建设的指导思想、原则与方法,并结合案例提出道路景观林改造模式,以实现森林公园由经济林转变为景观生态林的改造目标。