1. Three experiments were performed to study the effects of amino acid imbalance on the growth of genetically lean (LL) or fat (FL) male chickens from 28 to 42 d of age. In experiment 1, five concentrations of digestible lysine were compared (4.75, 6.75, 7.75, 8.75 and 9.75 g/kg). In experiment 2, four concentrations of digestible arginine were compared (6.53, 7.69, 8.84 and 10.0 g/kg). In experiment 3, three diets were compared: a high‐protein diet (189 g CP/kg), a low‐protein diet containing added essential amino acids (EAA) (144 g CP/kg) and this low‐protein diet supplemented with 40 g/kg of non‐essential amino acids (NEAA) (glutamic acid + aspartic acid).
2. LL birds exhibited a lower growth rate than the FL when the diet was deficient in either lysine or arginine. Plotting weight gain against lysine or arginine intake suggested that most of this effect was caused by variations in food intake.
3. When protein gains (body or total proteins) were plotted against lysine or arginine intake, LL chickens appeared more efficient than FL chickens.
4. Similar growth rates, although slightly lower in FL, were obtained with low‐ and high‐protein diets. However, NEAA supplementation of the low‐protein diet reduced adiposity of LL and did not modify that of FL. Increasing crude protein content (all amino acids) was more effective than NEAA supplementation in decreasing the adiposity of both lines. 相似文献
1. Diets containing a freeze‐dried tannin extract from faba beans (Vicia faba L.) at concentrations of 0, 8 and 16 g/kg were fed to growing chicks and rats.
2. Chicks fed on the tannin‐containing diets exhibited a high mortality and significant decreases in body‐weight as well as lower food intakes and higher food intake:weight gain ratios (P<0.01). In rats there was no mortality but the growth and food intake were adversely affected (P< 0.05).
3. Histological changes occurred in the ileal mucosa of chicks. Atrophy and shortening of villi with distortion of their architecture were observed. Similar histological disorders but less pronounced were also found in rats.
4. Histopathology of the liver of both chicks and rats showed an hydropic degeneration of hepatocytes, clearly more severe in the former than in the latter. 相似文献
Parameters derived from the non-invasive and simple monofrequency forced oscillation technique were compared with classical parameters of ventilatory mechanics in order to assess its usefulness for the investigation of pulmonary function in calves. To facilitate this comparison, theoretical derivations were coupled with in vitro measurements, using an artificial lung model, and with in vivo studies. These studies compared the oscillatory resistance parameters (Ros and Re) and the respiratory system compliance (Crs) against the classical pulmonary resistance (RL) and the dynamic compliance (Cdyn), respectively. Ros and Re were highly correlated (r0·87) with RL and the comparison between Crs and Cdyn gave a similarly high correlation (r0·88). Given its simplicity, its correspondence with classical parameters and its rapidity and reproducibility, monofrequency forced oscillation technique seems well suited for the investigation of pulmonary function under field conditions. 相似文献
SUMMARY: Additive genetic and maternal effects were estimated for postweaning growth traits and carcass traits using a derivate-free REML procedure under animal model. The traits studied were weight at 84 days of age, age at slaughter, postweaning ADG, dressing percentage, weight of kidney and pelvic fat, and muscle pH value and electrical conductivity in the semimembranosus muscle. Heritability estimates from a total of 728 rabbits in a reciprocal crossbreeding experiment ranged from 0.15 to 0.26 for postweaning growth traits, 0.21 for dressing percentage, 0.38 for weight of kidney and pelvic fat, 0.02 for pH value, and 0.51 for electrical conductivity. Considerable maternal effects were present in postweaning growth traits and in weight of kidney and pelvic fat. Genetic correlation estimates indicated that genetic selection for postweaning daily gain would lead to lower dressing percentages (- 0.51) and leaner carcasses (- 0.34). The genetic relationships between ADG after weaning and pH value (- 0.90), and between ADG and electrical conductivity (0.58) illustrated a shifting towards a glycolytic energy metabolism of the muscle due to increased growth. Litter size at birth was found to be a significant source of variation for all postweaning growth traits (p < 0.001) and for electrical conductivity (p < 0.05). Genetic selection for litter size at birth would result in decreased growth rates, lower dressing percentage and enhanced adiposis. ZUSAMMENFASSUNG: Die Sch?tzung additiv-genetischer und maternaler Effekte auf Mastleistungs- und Schlachtk?rpermerkmale beim Kaninchen Additiv-genetische und maternale Effekte wurden für Mastleistungsmerkmale nach dem Absetzen und für Schlachtk?rpermerkmale anhand eines Tiermodells (DFREML-Methode) gesch?tzt. Bei den untersuchten Merkmalen handelt es sich um das 84-Tage-Gewicht, das Schlachtalter, Zunahmen nach dem Absetzen, Ausschlachtungsprozente, Nieren- und Beckenfettgewicht und um den pH-Wert und die elektrische Leitf?higkeit im M. semimembranosus. Die Heritabilit?tssch?tzungen an insgesamt 728 Tieren, die aus einem reziproken Kreuzungsversuch stammten, lagen bei den Wachstumsmerkmalen zwischen h(2) = 0,15 und h(2) = 0,26. Sie betrugen h(2) = 0,21 für die Ausschlachtungsprozente, h(2) = 0,38 für das Nieren- und Beckenfettgewicht, h(2) = 0,02 für den pH-Wert und h(2) = 0,51 für die Leitf?higkeitsmessung. Die Sch?tzung genetischer Korrelationen deutet an, da? eine genetische Selektion auf t?gliche Zunahmen nach dem Absetzen zu einer verringerten Ausschlachtung (- 0,51) und zu magereren Schlachtk?rpern führen würde. Die genetischen Beziehungen zwischen den Zunahmen und dem pH-Wert (- 0,90) und zwischen den Zunahmen und der elektrischen Leitf?higkeit (0,58) lassen eine Verschiebung in Richtung eines glykolytischen Muskelenergiestoffwechsels bei verst?rktem Wachstum erwarten. Die Wurfgr??e bei der Geburt stellt eine signifikante Variationsursache für die Mastleistungsmerkmale nach dem Absetzen (p < 0,001) una für die elektrische Leitf?higkeit (p < 0,05) dar. Bei einer Erh?hung der Wurfgr??e durch Selektion sind verminderte Wachstumsraten, geringere Ausschlachtungsprozente und verst?rkte Verfettung zu befürchten. 相似文献
SUMMARY: Correct equations are given to express the parameter estimates of four models for complete diallels as a function of the parameter estimates in the model of Eisen et al. (1983). In recent literature these equations have been partly incorrect. ZUSAMMENFASSUNG: Korrekte Gleichungen für den Vergleich von Modellen in der Diallelanalyse Für die Darstellung der Parametersch?tzwerte von vier Modellen für vollst?ndige Diallele als Funktion der Parametersch?tzwerte des Modells von Eisen et al. (1983), die in der Literatur teilweise fehlerhaft erfolgte, werden korrekte Formeln angegeben. 相似文献