Genestic differences between successive year classes of two strains of reared rainbow trout, Oncorhynchus mykiss (Walbaum)

The genetic composition of consecutive year classes of two farmed rainbow trout, Oncorhynchus mykiss (Walbaum), strains was assessed, using starch gel electrophoresis of 11 enzymes encoded by a minimum of 23 loci, many of which have been shown to be polymorphic in previous studies. Angle frequencies at the majority of polymorphic loci varied significantly between year classes of each strain. Several alleles which were present at low frequency in the 1900 year classes, were absent in the samples from the 1991 cohorts. However, mean heterozygosity per locus (H) did not differ significantly between year classes of either strain, illustrating that allelic diversity is a more sensitive indicator of loss of genetic variability than mean heterozygosity. This heterogeneity between cohorts is probably due either to broodstock maintenance practices such as the use of insufficient numbers of spawners, or, in the case of one strain, to bottlenecking caused by selection for late maturation and increased growth rate. Genetic monitoring of all year classes of reared strains is suggested, if insufficient breeding and distribution records are available from egg producers. Such records are often unavailable in commercial situations.     

Disorders of the avian integument.

The avian integument consists of highly specialized structures that show extreme variations between species. Feathers are the most obvious part of the integument, and their color and beauty forms an important basis for the attraction of birds to humans. Any disorder in the feathers can be distressing for a client and frustrating for the avian practitioner. The cause of some disorders may be apparent, but others have a complex pathogenesis involving management, human-bird interaction, malnutrition, psychologic factors, disease, or hormone imbalances.     

Mass selection for kernel depth in early maize

Summary Effectiveness of mass selection for kernel depth in an early maize (Zea mays L.) synthetic, i.e. NDSAB, was evaluated in eight North Dakato environments. Four cycles of selection for deeper kernels were evaluated for grain yield and associated traits by using corresponding randomly selected subpopulations of NDSAB to adjust out inbreeding effects on selected subpopulations. General combining ability (GCA) effects of selected subpopulations also were evaluated for these traits.Subpopulations selected from one to four cycles for deep kernels were reciprocally crossed to corresponding randomly selected subpopulations in a factorial mating design. Subpopulations, selfed subpopulations, and subpopulation crosses were evaluated for yield and associated traits. Subpopulations selected for deep kernels generally had deeper kernels, higher yields, heavier kernels, more kernel rows per ear, and lower test weights than corresponding randomly selected subpopulations. Differences in GCA effects among selected and unselected subpopulations generally corresponded to differences between selected and unselected parental subpopulations. Inbreeding effects from selfing were observed for all traits, but no average heterosis was detected when subpopulation crosses were compared to parental subpopulations. Reciprocal differences were observed for all traits except kernel depth, but these differences were inconsistent relative to whether deep kerneled females made superior hybrids to unselected females.Results supported the use of mass selection for kernel depth as a means of grain yield improvement in the short term for NDSAB. However, negative associations of kernel depth with test weight may restrict long term use of this procedure.Journal Article No. 1505 of the North Dakota Agric. Exp. Stn., Fargo     

Enzyme-coenzyme complexes of pyridine nucleotide-linked dehydrogenases

Enzyme-reduced coenzyme binary complexes produce previously unreported shifts in the spectrum of the free coenzyme. These shifts give rise to difference spectra which resemble a general environmental change for reduced diphosphopyridine nucleotide (DPNH) in the glutamic dehydrogenase-DPNH complex, and indicate a more specific enzyme-coenzyme interaction for yeast alcohol dehydrogenase-DPNH, isocitrate dehydrogenase-TPNH, and lactic dehydrogenase-DPNH complexes.     

Uterine contractions in nonpregnant and early pregnant mares and jennies as determined by ultrasonography

Uterine contractions in 8 nonpregnant and 13 pregnant mares were studied using ultrasonography. A 1-min video tape recording was made of longitudinal real-time images of the uterine body. An overall uterine contractile activity score (0 = no or minimal activity to 4 = maximal activity) was assigned to each video tape segment. There was a day effect (P less than .01) and an interaction (P less than .01) of reproductive status X day. Uterine activity scores were highest on d 14 to d 18 (d 0 = day of ovulation) for nonpregnant mares and on d 10 to d 14 for pregnant mares. Uterine activity scores on d 10, d 12, and d 14 were greater (P less than .02) for pregnant mares (2.5 +/- .3, 3.1 +/- .3, and 3.2 +/- .1, respectively) than for nonpregnant mares (1.2 +/- .3, 1.5 +/- .3, and 2.6 +/- .3). Uterine activity scores for six pregnant and five nonbred jennies were assigned daily from d 0 to d 24. There were main effects of reproductive status and day (P less than .01) and an interaction of status X day (P less than .01). Uterine activity scores for pregnant jennies were highest on d 13 and d 14 and then declined. In the nonbred jennies, scores were highest on d 14 to d 20. The mean score on d 13 was greater (P = .05) in pregnant jennies (2.8 +/- .2) than in nonbred jennies (1.9 +/- .5).(ABSTRACT TRUNCATED AT 250 WORDS)     

Dermal cellular responses of helminth-free and Ostertagia ostertagi-infected calves to intradermal injections of soluble extracts from O. ostertagi L3 larvae

Twelve calves were raised helminth-free until 9 weeks of age when six were orally inoculated with 100,000 Ostertagia ostertagi infective stage larvae (L3). Three uninfected and three experimentally infected calves received intradermal injections of sterile saline and soluble larval extract (SLE) from O. ostertagi L3 with a protein concentration ranging from 1 to 200 micrograms ml-1. Biopsies were performed 48 h post-injection. A kinetic study was performed on the remaining six calves, three infected and three uninfected, using a 100 micrograms ml-1 concentration of SLE and taking biopsies 1, 4, 8, 12, 24, and 72 h post-injection at both the saline and SLE-injected sites. All calves had an immediate wheal and increase in skin thickness at the SLE-injected sites. The numbers of eosinophils infiltrating SLE-injected sites as compared to saline-injected sites were significant in both uninfected and infected calves, but the infected calves had significant numbers to a wider range of SLE concentrations and had significantly higher numbers than uninfected calves in the kinetic study. Infected calves also had significant numbers of basophils in the dose response study at concentrations of 5 and 100 micrograms ml-1 SLE. Neutrophil infiltration was similar in both groups and was significant at SLE-injected sites early in the kinetic study. Detectable mast cells were decreased in SLE-injected sites of infected animals and perivascular accumulation of mononuclear and some polymorphonuclear cells was observed in the deep dermis of infected animals.