Amino acid availability from selected animal‐ and plant‐ derived feedstuffs for market‐size sunshine bass (Morone chrysops × Morone saxatilis)

A study was conducted with market‐size (867 g) hybrid striped bass to determine the nutrient digestibility and apparent amino acid availability of six common feedstuffs. The animal‐protein feedstuffs tested were menhaden fish meal (MEN), anchovy fish meal (ANCH), pet‐food grade poultry by‐product meal (PBM‐pet), and feed‐grade poultry by‐product meal (PBM‐feed), while the plant‐protein feedstuffs were dehulled solvent extracted soybean meal (SBM) and distiller’s dried grains with solubles (DDGS). Test diets consisted of a 70 : 30 mixture of reference diet to test ingredient with chromic oxide (10 g kg^?1%) as the inert marker. Diets were randomly assigned to triplicate tanks of fish that were fed their respective diets for 7 days prior to fecal collection by stripping. Two feeding trials were conducted sequentially to determine the digestibility of the six test ingredients. In trial 1, the three ingredients evaluated were MEN, PBM‐feed, and PBM‐pet. In trial 2, the three ingredients evaluated were ANCH, SBM, and DDGS. Apparent digestibility coefficients of protein (ADC‐CP) were significantly (P < 0.05) different among test ingredients in trial 1 as protein digestibility of MEN (86%) was significantly higher (P < 0.05) than that of PBM‐feed (75%), but was not significantly different from that of PBM‐pet (78%). Protein digestibilities in trial 2 were not significantly different among test ingredients and averaged 76% for ANCH, SBM, and DDGS. Some apparent amino acid availability coefficients differed among feedstuffs for both trial 1 and trial 2. MEN provided higher amino acid availabilities for alanine, aspartic acid, glutamic acid, lysine, valine, and tryptophan (99%, 98%, 94%, 96%, 99%, and 108%, respectively) when compared to PBM‐feed (73%, 50%, 69%, 80%, 77%, and 91%, respectively) and PBM‐pet (79%, 66%, 81%, 81%, 78%, and 99% respectively). Glycine, histidine, leucine, and proline availabilities in MEN (95%, 96%, 100%, and 98%, respectively) were significantly (P < 0.05) higher than those of PBM‐feed (64%, 82%, 82%, and 57%, respectively), but were not significantly different from PBM‐pet (85%, 92%, 89%, and 80%, respectively). For trial 2, apparent amino acid availabilities for cystine, isoleucine, lysine, and tyrosine were significantly higher (P < 0.05) among treatments fed SBM (100%, 87%, 93%, and 97%, respectively) and ANCH (37%, 95%, 92%, and 84%, respectively) compared to treatments fed DDGS (?13%, 52%, 62% and 62%, respectively). Overall, amino acid availability in SBM and the two PBM’s appear comparable to MEN and ANCH and corroborate their high value as potential replacements for fish meal in sunshine bass diets. However, DDGS provided the lowest availabilities for several amino acids and should be used with caution.     

THE EFFECT OF MANUAL LUNG INFLATION VS. SPONTANEOUS INSPIRATION ON THE CARDIAC SILHOUETTE IN ANESTHETIZED DOGS

The purpose of this study was to assess radiographic heart size in anesthetized dogs, comparing radiographs made with the patient breathing spontaneously to radiographs obtained using positive pressure manual lung inflation. The hypothesis was that manual inflation would cause reduction in the cardiac size. With dogs in right recumbency a radiograph was made at peak spontaneous inspiration followed immediately a radiograph made with application of positive pressure manual inflation of the thorax. Cardiac size was assessed, both subjectively and objectively using the vertebral heart scale (VHS). Two hundred and six dogs were studied. Manual inflation resulted in a significantly greater degree of lung inflation assessed radiographically ( P <0.0001). The subjectively assessed heart size was significantly smaller in radiographs made with manual inflation, leading to different subjective categorization of heart size in 67 (32%) of dogs. The objectively measured VHS was also significantly smaller in the radiographs made using manual inflation by a mean of 0.24 of a vertebral length (95% CL of mean difference: −0.29, −0.19, P <0.0001). A statistically significant reduction in subjective heart size and in VHS occurred with manual inflation of the lungs, and these differences may be clinically significant. Thus, if serial radiographs are obtained to assess cardiac size, the radiographic technique used should be the same.     

Local disjunctive kriging of soil properties with change of support

Disjunctive kriging estimates from a set of measurements the conditional probability that true values of a regionalized variable such as a soil property exceed, or are less than critical thresholds. Estimates can be for sites equal in size to the supports of the samples and, by changing the support of the variogram, for larger blocks. The method also estimates the block averages and their associated variances. The underlying theory and steps in the analysis are described. They are illustrated using a case study from south-east Scotland where the aim is to estimate the likelihood of copper and cobalt deficiency over whole farms or 1 km² blocks of land using data from individual fields of 5 to 10 ha only. Maps show the conditional probabilities for 1 km² squares that the available copper in the soil is less than 1 mg kg^?1 and that cobalt is less than 0.25 mg kg^?1.     

Effects of feeding practical diets containing different protein levels, with or without fish meal, on growth, survival, body composition and processing traits of male and female Australian red claw crayfish (Cherax quadricarinatus) grown in ponds

Four practical diets containing 2% of crude protein (CP) (180 and 280 g kg^?1), with or without menhaden fish meal (FM), were fed to Australian red claw Cherax quadricarinatus during a 97‐day feeding trial. Growth, survival, body composition and processing traits of pond‐cultured red claw were determined. Juvenile red claw (mean individual weight of 5.75 ± 3.3 g) were randomly stocked into twelve 0.04‐ha ponds at a rate of 1000 per pond (25 000 ha^?1), and each diet was fed to three ponds. At harvest, the final mean weight of red claw fed Diet 4 (0 g kg^?1 FM and 280 g kg^?1 CP) and Diet 3 (113 g kg^?1 FM and 280 g kg^?1 CP) was significantly (P < 0.05) higher (62.4 and 58.5 g, respectively) than red claw fed Diet 1 (73 g kg^?1 FM and 180 g kg^?1 CP; 51.7 g) and Diet 2 (0 g kg^?1 FM and 180 g kg^?1 CP; 53.0 g). Red claw fed diets containing 280 g kg^?1 CP, with or without FM, had significantly higher percent weight gain (894 and 959%, respectively) compared to red claw fed 180 g kg^?1 CP, with or without FM (778 and 799%, respectively). Feed conversion ratio, percent survival, and total yield among treatments, which averaged 3.55, 65.2%, and 724 kg ha^?1 overall, were not significantly different. Results from this study indicate that pond‐cultured red claw stocked at 25 000 ha^?1 can be fed a practical diet containing 280 g kg^?1 CP with 0 g kg^?1 FM if a combination of plant‐protein ingredients (soybean meal, distillers’ dried grains with solubles, and milo) is added; however, if the percentage of dietary protein level is 180 g kg^?1, growth is reduced even if FM is added at 73 g kg^?1 of the diet. Use of diets containing plant‐protein sources may help reduce diet costs to producers and thereby, increase profits.     

A lysimeter study of the fate of nitrogen applied to perennial ryegrass swards: soil analyses and the final balance sheet

Labelled fertilizer nitrogen was applied at a rate of 40 g N m^?2 to grass swards growing in lysimeters containing monoliths of a sandy loam soil. After 5–7 years, during which time crop uptake and drainage losses of tracer nitrogen were measured, the soils were analysed to quantify the labelled nitrogen remaining. Approximately one-third (range 31–35%) of the applied labelled nitrogen remained, with over 70% of this residue located in the top 20 cm of soil. The rate of mineralization of immobilized tracer nitrogen declined exponentially; after four years the release rate was almost constant, and was equivalent to 2% of the residual labelled nitrogen. Total labelled nitrogen measured in crop, drainage and soil amounted to 93–98%. That unaccounted for was presumed lost by denitrification, largely in the form of dinitrogen, as measured rates of nitrous oxide emission were negligible. The recovery was greatest (and by implication, the gaseous loss smallest) when fertilizer was applied in 1975 during a particularly warm and dry summer.