Survival and Growth of White Bass Morone chrysops Reared at Different Salinities

Abstract.— Juvenile white bass Morone chrysops (age 158 d, 110.4 mm total length) were reared at salinity levels of 0, 4, 8, 12, 16, and 20 parts per thousand (ppt). Fish (10/tank) were stocked in 64-L tanks with four replicates/treatment ( N = 40heatment) and fed a pelleted feed daily. Fish were sampled semimonthly for 70 d. Fish reared at salinities of 12 ppt and below were significantly ( P ≤ 0.05) larger (mean = 151.5 mm total length; range 146.8–155.7 mm) than fish reared at salinities of 16 and 20 ppt (mean 133.7 mm total length; range 131.5–135.8 mm) after 70 d. Survival was also higher ( P ≤ 0.05) among fish reared at salinities of 12 ppt or lower (mean 85.6%; range 77.5%–92.5%) compared to those reared at the two highest salinities (42.5% survival at 16 ppt; 5.0% survival at 20 ppt). Thus, although typically found in freshwater habitats, white bass can survive and grow in brackish water.     

Effect of fats and fatty acid combinations on ruminal fermentation in semi-continuous in vitro cultures

Four in vitro trials were conducted to determine how ruminal fermentation is affected by source of fat, level of fat, and combinations of fatty acids. Trials I and II examined how volatile fatty acids (VFA) were changed by three sources of fat (blended animal-vegetable fat, corn oil and tallow fatty acids) each added to a hay substrate at six levels (0, 2, 4, 6, 8 and 10%). Increasing blended fat caused no changes in VFA levels except to decrease butyric acid from 12.1 to 9.9% of the total VFA (P less than .05). Corn oil and tallow fatty acids both increased propionic acid, causing the ratio of acetic to propionic acids (A/P) to decrease (P less than .01). Trial III tested different ratios of oleic/stearic and linoleic/stearic acids to determine if certain combinations were better for fermentation. There was no evidence of synergism among fatty acids since increasing the ratio of unsaturates steadily reduced A/P. Trial IV was designed to determine how changes in VFA levels reflect changes in fiber digestibility of substrates containing added fat. Volatile fatty acids having significant regressions with fiber digestibility were acetic acid (r = .648), propionic acid (r = -.670), total VFA concentration (r = .742) and A/P (r = .831). Results are interpreted to show that blended animal-vegetable fats are less toxic in the rumen than equal levels of other lipids, and the beneficial effects of blended fat cannot be attributed to a unique combination of fatty acids acting synergistically.     

Body composition and tissue distribution from birth to 14 months for three biological types of beef heifers

Thirty-four heifers were sampled randomly from each of the Hereford (He), Charolais (Ch) and Simmental (Si) herds at the U.S. Meat Animal Research Center at 2 d to 14 mo of age to examine body chemical composition and tissue distribution. Six heifers per breed were slaughtered after calorimetry at 2 d, 3 mo, 7 mo, 10 mo and 14 mo of age, and four others at 8 mo, to measure weight of empty body (EBW), water, fat, ash and protein as residual, in four fractions: carcass (CAR), head, hide and shanks (HHS), gastrointestinal tract plus internal fat (GIF) and visceral organs plus blood (VOB). Fasted live weight from birth to 14 mo increased from 39 to 414 kg for Ch, 38 to 385 kg for Si and 33 to 356 kg for He. Corresponding mean composition of EBW increased from 58 to 67% CAR and from 7 to 13% GIF but declined from 26 to 15% HHS and from 9 to 6% VOB. The water content of EBW declined from 73 to 51%, protein from 20 to 18% and ash from 4.3 to 3.5%, whereas fat increased from 3 to 28% and protein content of fat-free OM increased from 22% to 26%. Composition of CAR was similar to EBW but fat content increased more with age in GIF, less in HHS and least in VOB. Distribution of fat-free tissue changed from 58 to 66% in CAR, 26 to 18% in HHS, 7 to 8% in GIF and 9 to 8% in VOB. The EBW of Ch contained more CAR but less HHS than EBW of Si and HE. The EBW of Si and Ch contained more water and protein and less FAT than EBW of HE. The fatter He had proportionately less of their fat-free tissue in CAR (63%) and more in HHS (21%) and GIF (9%) than the Ch (66, 19, and 8%), with Si (64, 20 and 8%) intermediate. These age and breed differences in composition and tissue distribution may explain some of the variation in maintenance requirements.     

Transfer of drugs across the ruminal wall in goats.

The rates at which pentobarbital, salicylate, antipyrine, and quinine were transferred from the rumen of intact, conscious goats were measured. The rates at which the same drugs diffused from the blood plasma (under conditions of constant drug concentration) into the ruminal solution were also evaluated. These compounds were absorbed by simple diffusion, and the rates of transfer were a function of pH of the intraruminal solution. The diffusion of drugs from plasma into the reticulorumen allowed steady-state distributions to be established in some goats. The theoretical and observed steady-state distributions were compared. There were good correlations for pentobarbital and antipyrine, but not for salicylate and quinine. These findings confirm in vivo the general principles of drug transfer across ruminal epithelium that were derived from previous studies conducted in vitro.     

Genetic analysis without replications: model evaluation and application in spring wheat

Genetic data collected from various plant breeding and genetic studies may not be replicated in field designs although field variation is always present. In this study, we addressed this problem using spring wheat (Triticum aestivum L.) trial data collected from two locations. There were no intralocation replications and an extended additive-dominance (AD) model was used to account for field variation. We numerically evaluated the data from simulations and estimated the variance components. For demonstration purposes we also analyzed three agronomic traits from the actual spring wheat data set. Results showed that these data could be effectively analyzed using an extended AD model, which was more comparable to a conventional AD model. Actual data analysis revealed that grain yield was significantly influenced by systematic field variation. Additive effects were significant for all traits and dominance effects were significant for plant height and time-to-flowering. Genetic effects were predicted and used to demonstrate that most spring wheat lines developed by the South Dakota State University breeding program (SD lines) exhibited good general combining ability effects for yield improvement. Thus, this study provides a general framework to appropriately analyze data in situations where field crop data are collected from non-replicated designs.