Variation in plasma cholesterol concentration over time in the domestic fowl

1. Variations in the concentration of plasma cholesterol available to the developing oocyte over a three week period in Gallus domesticus are described.

2. There are small changes in concentration between weeks for individual birds, but no changes between consecutive days within weeks or times within days.

3. It is recommended that future attempts to assess the relationship between variation in blood and yolk cholesterol concentrations estimate blood cholesterol concentration from two samples taken a week apart.     

Chylous effusions revisited

Varying terms and criteria have been used in the veterinary literature to characterize milky opaque pleural effusions through the years. This article addresses ideas widely repeated in the veterinary and human literature upon which time, experience, diagnostic techniques, experimental data, and improved understanding of pathogenesis have cast doubt. Topics discussed include terminology, pathogenesis of chylous and pseudochylous effusions, criteria for differentiation of chylous from pseudochylous effusions, and clinicopathologic changes associated with drainage of chylous effusions.     

Comparison of the rates of proliferation of adipocyte precursor cells derived from two lines of chicken which differ in their rates of adipose tissue development

1. Putative adipocyte precursor cells were isolated from the white adipose tissue of young broiler and layer chickens and cultured in vitro.

2. The cells from both sources were shown to have the characteristics of adipocyte precursor cells. On reaching confluence, lipoprotein lipase activity was induced and the cells from both strains accumulated large amounts of lipid in the presence of chicken serum.

3. Measurement of cell number over time in culture and calculation of cell doubling times showed that cells from broilers proliferated at a faster rate than those derived from layer‐strain chickens. This was the case whether primary or secondary cell cultures were used. Primary cultures of broiler cells had a doubling time of 22 h versus 39 h for layer cells.

4. The contribution of such a difference in proliferative rate to the differential rate of adipose tissue growth between broiler and layer strains observed in vivo is discussed.     

Effects of pregnant mare's serum gonadotropin on reproduction in four genotypes of gilts(1)

SUMMARY: Effects of PMSG and genotype on various measures of reproductive efficiency were investigated. Prenatal data were obtained at 40 d of gestation from 96 gilts representing four genotypes. Data on Duroc (D), Yorkshire (Y), Synthetic (Large White × Landrace) (SYN), and Crossbred Duroc × Yorkshire (XB) gilts were collected from January, 1990 through May, 1991. Litter size (LS) data were collected from 482 farrowings of siblings. Treatment with exogenous hormones significantly increased number of corpora lutea (CL), number of embryos (EN), ovum wastage, (OVWS) and embryo length (ELG). Breed group differences (P < .05) were detected for natural ovulation rate, hormone-induced ovulation rate, CL, OVWS, ELG, embryo weight, ovum success, uterine length, ovary weight, range and variance of within-litter embryo weight (RWT and VWT), and litter size born alive. Natural ovulation rates for D, Y, SYN and XB were 10.46 ± 1.61, 12.64 ± 1.41, 14.10 ± .99 and 10.90 ± 1.47, and hormone-induced ovulation rates were 15.00 ± 1.53, 17.69 ± 1.40, 19.43 ± 1.17 and 12.19 ± 1.43, respectively. Range and variance of within-litter embryo length were not affected by either treatment or genotype. Increases in RWT and VWT observed in D and XB gilts after PMSG treatment did not adversely affect embryo survival to 40 d gestation. Significant genetic differences existed for litter size at birth. The PMSG treatment and interactions with PMSG were not significant for litter size born alive. Breed groups seem to differ for CL and EN in response to PMSG but only Yorkshire showed any response in LS (P < .10). Although PMSG increased ovulation rate in siblings by 4.06 ova and number of embryos at 40 d gestation by 1.87 compared with control gilts, there were no differences in litter size born alive due to PMSG treatment. The increase in ovulation rate and number of embryos generated by PMSG seems to be negated by fetal losses occurring both before and after 40 d of gestation. ZUSAMMENFASSUNG: Einflüsse von Stutenserum-Gonadotropin (PMSG) auf Reproduktionsmerkmale von vier Genotypen bei Jungsauen Einflüsse von PMSG und Genotyp auf verschiedene Merkmale der Reproduktion wurden untersucht. Daten wurden am 40. Tr?chtigkeitstag von 96 Jungsauen von vier Genotypen-Duroc (D), Yorkshire (Y), Synthetik (Edelschwein × Landrasse (SYN)) und Kreuzungen-Duroc × Yorkshire (XB) zwischen Januar 1990 und Mai 1991 erhoben. Wurfgr??e (LS) wurden von 492 Würfen von Geschwistertieren erhoben. Behandlung mit exogenem Hormon steigert signifikant die Zahl der Gelbk?rper (CL), Zahl der Embryonen (EN), Ovarverlust (OVWS) und Embryol?nge (ELG). Differenzen zwischen Genotypen wurden für natürliche und hormoninduzierte Ovulationsrate, CL, OVWS, ELG, Embryogewicht, Embryoerfolg, Geb?rmutterl?nge, Ovargewicht, Streuungsbereich und Varianz des Embryogewichtes von Wurfgeschwistern (RWT und VWT) und Zahl lebendgeborener Ferkel erhoben. Die natürlichen Ovulationsraten für D, Y, SYN und XB waren 10,46 ± 1,61, 12,64 ± 1,41, 14,10 ± 0,99 und 10,90 ± 1,47, und die hormoninduzierten 15,00 ± 1,53, 17,69 ± 1,40, 19,43 ± 1,17 und 12,19 ± 1,43. Streuungsbereich und Varianz zwischen Embryonenl?nge eines Wurfes wurden weder durch Behandlung noch Genotyp tangiert. Steigerungen in RWT und VWT in D und XB Jungsauen nach Hormonbehandlung hat Embryoüberleben bis 40 Tage nicht beeintr?chtigt. Signifikante genetische Unterschiede existieren zwischen Wurfgr??e bei Geburt. Hormonbehandlungen und Interaktionen mit Genotypen waren für die Wurfgr??e nicht signifikant. Rassengruppen scheinen für CL und EN im Hinblick auf Hormonbehandlung sich zu unterscheiden, aber nur Yorkshire zeigten Reaktion bei LS (P < .1). Obwohl das Hormon die Ovulationsrate um 4,06 Eier und Zahl der Embryonen bei 40 Tagen um 1,87 gegenüber Kontrollsauen vergr??erte, verblieben keine Unterschiede in Wurf gr??e. Die Steigerung der Ovulationsrate und Zahl der Embryonen nach Hormonbehandlung scheint durch F?talverluste vor und nach 40 Tagen Tr?chtigkeit eliminiert zu werden.