Muscle growth in wild and domestic ducks

1. Increases in weight of the M. pectoralis, M. iliotibialis lateralis and M. flexor cruris lateralis were measured in mallards, White Pekins, Muscovies and a Muscovy × White Pekin cross from hatching to 154 days of age. Growth with respect to age was analysed using the Janoschek growth curve. 2. The M. pectoralis was less developed at hatching than both leg muscles. Furthermore, it showed a slower growth to its final weight and a later age at maximum growth than both leg muscles. 3. Pekins exhibited a faster Pectoralis and Iliotibialis lateralis muscle growth than mallards and Muscovies. The latter attained greater weights than Pekins at later ages owing to a higher asymptote. The cross showed the fastest muscle growth. 4. With respect to body weight, the Pectoralis is characterised by isometry followed by strongly positive allometry. This multiphasic allometry implies that relative muscle weights should not be used and the value of the allometric exponent strongly depends on both the beginning and duration of the period of investigation. Leg muscles showed isometric to slightly negative, simple allometry.     

Wachstum von Bursa Cloacalis (Fabricii) und Milz bei Enten

The growth in weight of both the bursa of Fabricius and the spleen was investigated in different stocks of ducks between hatching and 154 days of age. The data were analysed by fitting the Janoschek growth curve and the allometric formula. Both organs showed rapid growth to their maximum dimensions and early points of inflection. The regression of the cloacal bursa started at about 12 weeks of age in Pekins and Mallards. In the Muscovy, the involution begins beyond the period of investigation. Allometrically, a biphasic relationship was found. Starting with positive allometry, the allometric exponent decreased to negative or isometric (Muscovies) values within the second week of age. If the organ weights are compared on the basis of these allometric relationships, Pekins had bursa weights that were about 30% higher than those in Mallards. For the spleen, there was no difference between wild and domesticated ducks.     

Growth curve analyses in selected duck lines.

1. Growth patterns of male ducks from 4 lines (lines A, B, C and D) selected for market weight were analysed and compared to growth patterns of ducks in the respective line 7 generations earlier. Growth curves were analysed using procedures derived from the Weibull sigmoidal function and the linear-linear relative growth rate model and simple allometry. 2. The ducks were fed ad libitum under 24-h lighting throughout the experiment. At weekly intervals from the time of hatch through 70 d of age, 16 ducks from each line were killed to determine body, carcase, breast-muscle, leg and thigh-muscle, and abdominal fat weights. 3. Line A was the heaviest line, followed by line B, line C and line D. However, body weight, carcase weight and breast-muscle weight at 49 d of age were not significantly different between lines A and B. After 7 generations of selection, the breast-muscle yield was increased to >19% and the abdominal fat percent was reduced to <1.4% in all lines. 4. The Weibull growth curve analysis of body weight showed an increase in the asymptotes during selection, while the age of the inflection point remained constant in all lines (21.3 to 26.0 d). For breast-muscle growth, ducks reached the inflection point 12.8 to 14.3 d later than for body weight. Between line A and line B, asymptotes for body weight, asymptotes for breast-muscle weight and allometric growth coefficients of breast muscle and leg and thigh muscles from 14 to 49 d were not significantly different. 5. The relative growth rate model discriminated body and breast-muscle growth patterns of line A and line B. The initial decline in the relative body growth rate was less and the time to reach the transition was longer in line A than line B. On the other hand, the initial decline in the relative breast-muscle growth rate was greater in line A than line B.     

Experimental Analysis on Allometric Growth in Spualiobarbus curriculus Larvae and Juveniles in Zhaoqing Reach of the Pearl River

Ecological experiment was conducted in this paper to study the allometric growth in Squaliobarbus curriculus larvae and juveniles from Zhaoqing Reach of the Pearl River. The results showed that after first feeding, the organs associated to swimming, feeling and feeding of larvae differentiated rapidly, and exhibited allometric growth. The head length, tail length and head height exhibited positive allometric growth, while trunk length exhibited negative allometric growth before reaching the growth inflexion point 20 d after first feeding, and positive allometric growth after the inflection point. Body height exhibited positive allometric growth both before and after the growth inflexion point at 18 d after first feeding. The inflexion points of snout length, eye diameter and post-eye head length occurred 23, 19 and 16 d after first feeding. For swimming organs, the dorsal fin, pelvic fins and anal fin exhibited positive allometric growth both before and after the inflexion point at 18, 19 and 17 d after first feeding; but the tail fin exhibited positive allometric growth before the inflexion point at 14 d after first feeding, and negative allometric growth after the inflexion point. S. curriculus larvae can possess various abilities soon after first feeding to survive at early stage due to the rapid development of swimming, feeling, feeding and other organs, which has important ecological significance to adapt to the complex external environment.     

Growth pattern and carcase development in male ducks selected for growth rate.

1. Growth patterns of the whole body, eviscerated carcases, breast muscle, leg and thigh muscles and abdominal fat pads were compared in 4 lines (Lines A, B, C, and D) of male ducks selected for market weight (n = 1305) using growth curve analysis, allometric growth analysis and repeated measure analysis. At 49 d of age, Line A was heaviest, followed by Line B, Line C and Line D. 2. Ducks were fed ad libitum under 24-h lighting and 12 or 24 ducks were killed to determine body, carcase, breast-muscle, leg and thigh-muscle, and abdominal fat weights at time points from hatching until 53 d of age. 3. The Weibull function was chosen for growth curve analysis. The asymptote and inflection point from the Weibull growth curves identified 3 lines (Lines B, C, and D) with discrete body and carcase growth patterns but did not distinguish Line A from Line B. In all 4 lines the asymptote ranged from 4437 g to 3008 g for body weight and from 3334 g to 2098 g for carcase weight; the inflection point ranged from 22.5 d to 25.3 d for body weight and from 25.4 d to 29.6 d for carcase weight. 4. The allometric growth coefficient, relative to whole-body growth, was higher than 1.00 for breast muscle and lower than 1.00 for leg and thigh muscles during from 4 d to 53 d of age. 5. Body fat accumulation was estimated by abdominal fat. Line D accumulated more abdominal fat than other lines. The pattern of fat accumulation in Line D was different from Lines A, B and C and there were no differences between Lines A, B and C.     

Growth and development of the digestive organs and some enzymes in broiler chicks after hatching.

1. Body weight and the weight of the digestive organs and activities of some digestive enzymes were determined from hatching to 23 d of age. 2. Relative daily growth rate peaked at 11 d of age (22% gain/d) and then decreased gradually. 3. The vitelline residue was decreased rapidly from 4.6 g at hatching to negligible values from 4 d of age. 4. Maximal allometric growth of the pancreas and small intestine was 4-fold and that of liver 2-fold greater than that of the body. 5. Activities (units/kg body weight) of the digestive enzymes measured in the pancreas and intestinal contents increased with age. In the pancreas maximal values were attained on day 8 for amylase and lipase and 11 for trypsin and chymotrypsin. In the small intestine maxima were attained on day 4 for lipase, 11 for trypsin and chymotrypsin and 17 for amylase. 6. The development of secretion of digestive enzymes in the post-hatched chick could be a limiting factor in digestion and subsequently in food intake and growth.     

Allometric basis of enrofloxacin scaling in green iguanas

When body size varies greatly, drug disposition can best be described as an allometric function of body weight. Therefore, the allometry of standard metabolic rate (SMR; 3/4 power) and body surface area (BSA; 2/3 power) have been advocated as surrogate markers for the prediction of key pharmacokinetic parameters. The goal of the present study was to examine the allometric basis of pharmacokinetic scaling within a species, green iguanas. Enrofloxacin was administered intravenously to 20 green iguanas (322-3824 g), and noncompartmental analysis was used to calculate standard pharmacokinetic parameters, which were log(10) transformed and regressed against log(10) body weight. The slopes of significant regressions were compared with the values of unity, 3/4, and 2/3. The slope of enrofloxacin total body clearance (Cl) was also compared with the slopes relating SMR and renal Cl of (99m)Tc-diethylenetriamine penta-acetic acid ((99m)DTPA) to body weight in iguanas. Enrofloxacin Cl depended allometrically on body weight with the power of 0.32. The slope of enrofloxacin Cl was significantly less than those of SMR, Cl of (99m)DTPA, and the 2/3 value. Therefore, the relationship between enrofloxacin Cl and body weight does not directly depend on the allometry of BSA, SMR, or renal Cl of (99m)DTPA in iguanas.     

Effects of body weight at, and lighting regimen and growth curve to, 20 weeks on laying performance in broiler breeders

1. A total of 4000 Ross broiler breeders were reared to a 20-week target body weight of 1.55, 2.16 (standard), 2.50 or 2.84 kg, using either a convex or concave growth curve. Each treatment group was either exposed to a conventional broiler breeder lighting regimen, with a series of weekly one-hour increments in photoperiod from 8h at 19 weeks to a 16-h maximum, or maintained from 4d on a 17-h photoperiod. 2. Each 100 g increment in body weight at 20 weeks was associated with a significant increase of 0.55 kg in cumulative food intake, and a 1.5-d advance in sexual maturity. However, leaner body weights at 20 weeks resulted in smaller body weight gains between 20 and 60 weeks (-2.4 g/d/kg body weight at 20 weeks), and an increased production of double-yolked eggs. Neither egg production nor mean egg weight was affected by 20-week body weight. 3. Birds fed to produce more rapid early growth had higher feed intakes to 20 weeks, but reached sexual maturity 7 d later than birds permitted accelerated growth from 15 weeks. Growth curve did not influence body weight gain in lay, egg production or mean egg weight. 4. Birds maintained on 17-h photoperiods reached sexual maturity 27 d later, produced 7 fewer eggs to 60 weeks, and had a mean egg weight 1.2 g heavier than birds photostimulated at 19 weeks. Lighting treatment did not affect food intake to 20 weeks, the proportion of double-yolked eggs or body weight gain between 20 and 60 weeks. 5. Birds fed to have a faster growth early in the rearing phase and maintained on 17-h photoperiods produced 11 fewer eggs than those fed to have accelerated growth at the end of the rearing phase, yet there was only one egg difference between the growth-curve groups for the conventionally lighted birds, which was not significant. 6. The earlier sexual maturity of the conventionally lighted birds compared with those maintained on 17-h photoperiods either indicates that broiler breeders require an increment in photoperiod to stimulate rapid gonadal development or that broiler breeders exhibit juvenile photorefractoriness that takes longer to be dissipated when birds are not given a period of short days. 7. The findings suggest that a nutritional stimulus late in rearing is only necessary for satisfactory egg production if birds have not received a concurrent increment in photoperiod.     

Early and temporary quantitative food restriction of broiler chickens. 2. Effects on allometric growth and growth hormone secretion

1. An experiment was conducted with male broiler chickens to investigate the effect of different early food restriction programmes on proportional weights and allometric growth coefficients of carcase parts and on pulsatile growth hormone secretion. 2. At 4 d of age the animals were restricted to 80% or 90% of the ad libitum intake for 4 d or 80% for 8 d. When the restriction was finished, all birds received ad libitum food again. 3. On d 1, 8, 11, 14, 21, 28, 35 and 42, from each group 8 birds were weighed, stunned and killed and the weights of the stomachs, liver, heart, sternum, right thigh, right drumstick, breast and abdominal fat pad were determined. On d 29, 30, 31, 32 serial blood samples of 2 birds from each group were taken to determine the plasma growth hormone (GH) content. 4. Only the most severe restriction resulted in a tendency for the stomachs to mature earlier and the thighs to mature later. No other significant effect on the allometric coefficients could be observed. 5. It is concluded that during the restriction the birds give priority to the development of the supply organs such as the stomach, which are more important during early development at the expense of the demand tissues like breast and thigh. 6. No significant differences concerning the GH secretory parameters could be observed.     

The effect of increasing photoperiod and food restriction in sexed broiler-type birds. I. Growth and abdominal fat cellularity.

1. Sexed broiler-type chicks were raised either under a continuous (CON) 23 h Light (L) and 1 h Dark (D) schedule or an increasing photoperiod (INC) consisting of an initial 6 h L and 18 h D which increased by 4 h L per week from 14 to 35 d of age after which a 23 L:1D was maintained to 49 d of age. 2. From 5 to 11 d of age birds were fed either: ad libitum (AL), energy intake (kJ ME) restricted to 9.414 x gBW0.67 (R1) or energy intake (kJ ME) restricted to 6.276 x gBW0.67 (R2). Food intake was ad libitum at all other times. 3. Food restriction reduced growth to 49 d of age although some compensatory growth did occur. Food efficiency was not significantly affected by restriction. 4. Although abdominal fat pad weight was significantly reduced for R2 compared to AL, this was not significant on a percentage body weight basis. 5. Adipocyte number in the abdominal fat pad was similar for AL, R1 and R2, but concomitant with a smaller fat pad weight, R2 showed reduced adipocyte volume compared to AL. 6. INC birds were lighter at 21 d of age, but body weights were equivalent to CON by 42 d of age. 7. Abdominal fat pad weight was some 10% larger at 49 d of age for INC birds. Adipocyte volume was unaffected, the increase in adipocyte being entirely caused by an increase in adipocyte number in INC birds.     

早期限饲对肉鸡补偿性生长的影响

试验观察了几种早期限饲措施对肉鸡补偿性生长和消化器官发育的影响。结果显示,各种早期限饲处理均可明显降低肉鸡早期的生长速度和体重;恢复自由采食后肉鸡获得了补偿性生长,适当的早期限饲并不影响肉鸡的最终上市体重;早期限饲改善了饲料效率;限饲鸡胰脏相对重量和肌胃 腺胃相对重量显著高于非限饲鸡,提示早期限饲诱发肉鸡补偿性生长可能与限饲促进消化器官发育、提高消化能力有关。     

Effects of mushroom and herb polysaccharides, as alternatives for an antibiotic, on growth performance of broilers

(1) This in vivo trial was conducted to study the effects of polysaccharide extracts of two mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and a herb, Astragalus membranaceus (AstE) on growth performance, and the weights of organs and the gastrointestinal tract (GIT) of broiler chickens. (2) Three extracts (LenE, TreE and AstE) were supplemented at inclusion rates of 0.5, 1, 2, 3 and 4 g/kg from 7 to 14 d of age and compared with an antibiotic treatment group (20 mg/kg, virginiamycin (VRG) as well as a group of non-supplemented birds. (3) Body weight (BW) gain, feed intake and feed conversion ratio (FCR) of the extract-supplemented groups were not significantly different from those of the antibiotic group. Significant effects of type of extract and concentration on growth performance were found from 7 to 28 d of age. Generally, birds fed with LenE showed higher BW gain and lower FCR from 7 to 28 d of age than those fed with TreE and AstE and 2 g/kg LenE was considered the optimal inclusion rate for enhanced broiler growth. However, the extracts had no significant effect on the relative weights of organs and GIT compared with the antibiotic group. (4) The birds fed the extracts showed better growth performance than the non-supplemented birds, but were not significantly different from those fed VRG. Of the three extracts, LenE appeared to be a potential growth promoter. Future studies are needed to investigate whether the extracts can be used as alternatives for antibiotic growth promoters in challenged birds, and to elucidate the mechanisms for potentially enhanced growth performance in poultry.     

白刺叶片解剖结构性状异速生长与生态适应性研究

本实验以不同生境下3种白刺(西伯利亚白刺、大果白刺、唐古特白刺)叶片为研究对象,测量3种白刺的叶片解剖结构中叶片厚度、上角质层厚度、上表皮厚度、栅栏组织厚度、海绵组织厚度、下表皮厚度和下角质层厚度等性状指标,用经典异速方程(Y=βX^α)描述叶片解剖性状之间的关系。结果表明：不同生境的白刺叶片解剖性状均有显著性差异(P＜0.05),均呈显著性幂指数异速生长关系,其异速系数表现显著性差异(P＜0.05),其异速指数表现出两类完全不同的规律,一类是≈1,另一类是＜1,存在着资源分配的权衡。不同生境白刺叶片解剖性状的变异系数在0.10～0.45之间,属于相对稳定的系统演替性状。植物生境中的海拔高度、年降水量与年蒸发量是影响叶片性状的主要因素,3种白刺通过长期的外界异质性的环境因子驱动改变叶片结构性状,可以使其在不同的生境下朝着最适的异速生长曲线进化。     

Allometric analysis of ciprofloxacin and enrofloxacin pharmacokinetics across species

The purpose of this study was to examine the allometric analysis of ciprofloxacin and enrofloxacin using pharmacokinetic data from the literature. The pharmacokinetic parameters used were half-life, clearance and volume of distribution. Relationships between body weight and the pharmacokinetic parameter were based on the empirical formula Y = aW(b), where Y is half-life, clearance or volume of distribution, W the body weight and a is an allometric coefficient (intercept) that is constant for a given drug. The exponential term b is a proportionality constant that describes the relationship between the pharmacokinetic parameter of interest and body weight. A total of 21 different species of animals were studied. Results of the allometric analyses indicated similarity between clearance and volume of distribution as they related to body weight for both drugs. Results of the current analyses indicate it is possible to use allometry to predict pharmacokinetic variables of enrofloxacin or ciprofloxacin based on body size of species. This could provide information on appropriate doses of ciprofloxacin and enrofloxacin for all species.     

Growth response, blood characteristics and copper accumulation in organs of broilers fed on diets supplemented with organic and inorganic dietary copper sources

1. A 56-d experiment was conducted to study the comparative influence of organic and inorganic dietary copper (Cu) sources on growth, blood characteristics and copper accumulation in organs of broilers. 2. A total of 480 Arbor-Acre unsexed broilers were fed on diets containing copper sulphate (CuSO(4)) or copper proteinate (Cu Pro) at concentrations of 50, 100 or 150 mg/kg of Cu supplementation. The birds were given a broiler starter diet from 1-28 d and a broiler finisher diet from 29-56 d which contained 30·8 mg/kg and 41·1 mg/kg basal copper concentration respectively. Growth performance, blood characteristics and Cu accumulation in organs of the broilers were measured. 3. At 28 d, Cu Pro-fed birds had improved feed conversion ratio compared with CuSO(4). At 56 d, birds fed on Cu Pro diets had significantly greater body weight than CuSO(4)-fed birds. Birds fed on CuSO(4) supplemented diets had significantly better feed conversion efficiency. Feed consumptions for the two Cu sources were not significantly different. At no stage did the concentration of added Cu affect the productive traits measured. 4. Cu Pro supplementation increased haemoglobin concentration but reduced plasma triglyceride and plasma cholesterol. Plasma cholesterol decreased as Cu concentration increased. 5. There was a greater accumulation of Cu in the blood, heart, lung, liver and bone of broilers fed on Cu Pro than in those receiving CuSO(4). The liver Cu concentration increased as dietary Cu concentration increased. 6. Cu Pro was more effective in promoting growth and reducing blood cholesterol, and was more bio-available in the organs of broilers.     

Prepuberal Ovine Mammary Development is Unaffected by Ovariectomy

Crossbred ewe lambs were used in a 2 × 2 × 2 factorial design to determine the effect of ovariectomy, age, and estrogen administration on prepuberal mammary development. Intact (I, n = 20) and ovariectomized (OVX, n = 17) lambs were sacrificed at 6 and 13 wk of age after 1 wk of either estrogen 0.1 mg/kg BW/day, s.c.) or vehicle injections. Ovariectomies were performed at 10 ± 1 d of age. At sacrifice, one mammary gland was dissected into parenchymal and stromal fractions for biochemical analyses. Parenchymal explants from the remaining gland were labeled with [³H]thymidine for histoautoradiography. Neither ovariectomy nor estrogen treatment affected body weight, total gland weight, or parenchymal weight (P > 0.05). However, means for each of these variables increased between 6 and 13 wk (P < 0.01). Analysis of relative mammary growth showed significant positive deviations from isometry. However, no significant difference in parenchymal allometry was observed between I and OVX groups. Exogenous estrogen stimulated an increase (P < 0.05) in epithelial cell labeling with [³H]thymidine, but neither ovariectomy nor age at sacrifice had any effect (P > 0.2) on epithelial labeling. These results demonstrate that prepuberal allometric mammary growth in the ewe lamb does not require the presence of the ovary.     

Rearing photoperiod and abrupt versus gradual photostimulation for egg-type pullets

1. Lohmann White and Lohmann Brown egg-type hybrids were reared on 6-, 8-, 10- or 12-h photoperiods, transferred to 12.5 h at 18 weeks and then given weekly increments to reach 14 h at 21 weeks. In a second experiment, Lohmann White pullets from the same rearing facility were transferred abruptly to 14 h at 18 weeks. 2. Body weight gain and feed intake to 6 and 18 weeks were positively correlated with rearing photoperiod in both breeds. Mortality to 18 weeks was unaffected. 3. Whether the photoperiod was increased abruptly or in a series of increments, Lohmann White pullets reared on 6 or 8 h matured 4 to 6 d later than pullets reared on 10 or 12 h. Rearing day-length had little effect on sexual maturity in Lohmann Brown pullets. 4. In both genotypes and each experiment, egg numbers, egg weight and shell strength increased with rearing photoperiod. Feed intake in the laying period was not significantly affected by rearing day-length, but a meta-analysis of all data showed a significant, though small, increase in adult feed intake with rearing photoperiod. Despite Lohmann White birds reared on 6 and 8 h having lower body weights throughout the laying period, they had larger body weight gains between 18 and 70 weeks than those reared on 10 or 12 h. There were no clear effects of rearing photoperiod on albumen height or mortality. 5. The heavier eggs and stronger shells of the birds reared on the longer day-lengths were correlated with heavier body weights at 18 weeks, and the superior egg numbers and higher feed intake were associated with age at sexual maturity.     

Differential compensatory growth in swine following control of feed intake by a high-alfalfa diet fed ad libitum or by limited feed

Seventy-two castrated male four-way composite (Chester White x Landrace x Large White x Yorkshire) weanling pigs (17 kg initial BW) were used to determine the compensatory response of specific organs and whole body following a 3-wk period of restricted energy intake imposed by ad libitum-feeding an 80% alfalfa meal diet or pair-feeding an adequate corn-soybean meal diet to attain equal weight loss. Six pigs were killed at d 0 to provide baseline data. Six pigs from each diet group (control, C; alfalfa, A, restricted, R) were killed at d 21, after which all remaining pigs were fed C ad libitum to 35 d, 105 d or 126 d. Six pigs per group were killed at 35 and 105 d and four per group were killed at 126 d. Organ weight and carcass data were recorded for all pigs at all time intervals. Regression of organ and trimmed lean tissue weights on time was tested for linearity (d 1 to 126 for C and d 21 to 126 for A and R except d 35 to 126 for gastrointestinal tract traits for A and R); differences in organ weights between C, A and R at d 21 and d 35 were tested by a two-way analysis of variance. There was no evidence of a compensatory growth response to dietary energy restriction for 21 d except for rate of change in weights of liver and kidneys and backfat depth from 21 to 126 d and of gastrointestinal tract components from 21 to 35 d. Specific organs may exhibit compensatory growth over different time spans in young pigs in the absence of observable weight compensation at the whole-animal level.     

灰绿藜形态性状与繁殖性状的异速关系

通过对不同光照强度、营养和萌发时间处理条件下灰绿藜的形态指标和繁殖指标的测定,本研究探讨了灰绿藜形态性状和繁殖性状之间的异速关系及其异速生长对环境变化的响应。结果表明:灰绿藜形态性状与繁殖性状之间存在显著的异速生长关系,随着灰绿藜个体大小的增大,单个枝条的大小增速更快,并且将更多的资源分配到灰绿藜的繁殖生长。但灰绿藜的花序密度与个体大小之间具有显著的权衡关系:灰绿藜越小,花序密度越高。光照处理引起植物的繁殖性状发生了变化,但是这些变化主要是由在光照梯度下的个体大小不同造成的,繁殖策略(异速生长)未发生改变。而营养及萌发时间处理对灰绿藜的形态性状与繁殖性状间的异速关系产生了影响。营养变化对不同性状间的异速关系无一致影响,而萌发时间则具有显著的影响,晚萌发的灰绿藜将更多的资源投入到繁殖生长。