Feed Restriction in Laying Hens

Summary Landscape‐scale clines in environmental parameters can lead to life‐history gradients. Study of interspecific life‐history differences can provide evidence of evolutionary adaptations in response to environmental cues, whereas examination of intraspecific life‐history variation can identify the ecological mechanisms driving trait evolution. We examined egg size and fecundity variation in three species of closely related freshwater fish (Galaxiidae) which occur across a habitat gradient in South Island, New Zealand. Inter‐population trait variation was assessed in the species with the widest distribution to investigate the ecological mechanisms driving egg size evolution. Substantial interspecific egg size and fecundity differences were observed. Galaxias paucispondylus, which generally occurs in high altitude headwater streams, showed an average egg size an order of magnitude larger, and fecundity an order of magnitude lower than G. brevipinnis, a species which rears in pelagic environments. Galaxias vulgaris, which rears fluvial environments but is generally distributed in lower catchment reaches than G. paucispondylus, showed intermediate fecundity and egg size traits. This interspecific trait variation is likely to be driven by differences in the larval rearing habitat, i.e. rearing in cold high altitude locations requires large well‐developed larvae (and therefore large eggs) but these come at the cost of maternal fecundity, whereas in rearing in warmer lower catchment watercourses, and pelagic habitats, does not require such large well‐developed larvae. Hence, fitness is maximised by progressively increasing fecundity by reducing egg size across this habitat cline. Life history‐habitat trends were repeated when intraspecific patterns in the widely distributed G. vulgaris were assessed, with population egg size increasing, and fecundity decreasing, in relation to a suite of interrelated environmental variables up an approximate altitudinal cline. The results highlight how inter‐ and intraspecific variation in egg size–fecundity trade‐offs in closely related species can interact to drive the evolution of landscape‐scale life‐history gradients. Egg size differences are likely to be driven by differences in the quality of the larval rearing habitat, i.e. rearing in a challenging habitat requires a larger egg whereas in relatively benign larval rearing habitat, fecundity can be maximised by reducing egg size. The interspecific variation observed provides evidence of trait adaptation in response to an environmental cue, while the intraspecific inter‐population differences indicate the potential ecological mechanisms driving trait evolution.

Two big bluestem (Andropogon gerardii Vitman) strains (Pawnee C3 and Kaw C3) developed by three breeding cycles for increased forage yield and in vitro dry matter digestibility (IVDMD) were compared with the base populations of ‘Pawnee’ and ‘Kaw’ in a 3‐yr grazing trial. Pastures were seeded in May 1998 near Mead, NE. Experimental units were three 0.4‐ha pastures of each strain or cultivar in a randomized complete block design. Pastures were burned and fertilized with ammonium nitrate at 112 kg N ha−1 in the spring of 2000, 2001, and 2002 before grazing. Each pasture was continuously stocked with three crossbred yearling steers (Bos taurus) (380 ± 38 kg) in mid‐June 2000, 2001, and 2002 to provide a stock density of 7.5 steers ha−1 Pawnee C3 and Kaw C3 produced 16 and 7% more average daily gain (ADG), respectively, than the base populations during the 3‐yr study. Additionally, Pawnee C3 and Kaw C3 produced 14 and 5% more total body weight (BW) gain ha−1, respectively, than the base populations. Pawnee C3 ADG was 1.30 kg hd−1 and produced greater than 455 kg total BW gain ha−1 during a drought period in eastern Nebraska. Pawnee C3 pastures produced more available forage with higher IVDMD, cell soluble, cell wall digestibility, and lower lignin concentration than forages from Pawnee pastures. Kaw C3 pastures differed from Kaw pastures by producing forage with greater crude protein concentration. These results demonstrate the productivity of big bluestem pastures in the eastern Great Plains and document the positive livestock response to moderate increases in forage IVDMD. The strains bred for increased yield and IVDMD provided as much as 26% more total BW gain ha−1 at no additional cost. Pawnee C3 was released as the cultivar Bonanza and Kaw C3 was released as ‘Goldmine’.

Abstract. Measurements of egg number, egg size and total egg volume in relation to post-stripped weight, made on the eggs stripped from 12 separately maintained farm stocks of 4-year-old rainbow trout. Oncorhynchus mykiss Richardson, revealed highly significant differences between populations when analysed by regression and covariance statistical techniques. All of the stocks showed increases in fecundity with increasing fish size, with 61% (coefficient of determination or r2) of the variation in fecundity of the 12 stocks explained by the common regression on parental fish size. Comparison of the regressions of the different stocks revealed that the rate of increase of fecundity with increasing fish weight was constant throughout the weight range (i.e. the regressions had similar slopes) although there were highly significant differences in elevation, with some stocks producing almost twice as many eggs as some of the others. By contrast, the relationship of egg size with fish weight was much more variable with three of the stocks showing no significant regression of egg size on fish weight and a further two stocks with data poorly fitted to the regressions. Of the remaining seven stocks only one showed a significant difference in slope of the regression with modest increases in fish weight being associated with large increases in egg size. Only four of the remaining stocks of fish showed significant differences in the elevation of their regressions, i.e. the egg sizes were significantly different after the potentially conflicting influence of fish size was partitioned using covariance techniques. Assessments of total egg volume produced far improved regressions on post-strip weight with 75% (r2) of the variation in the pooled data of the 12 stocks being described by the line of the common regression. In general, there appeared to be a “trade-off” between egg number and size with the most and least fecund fish producing somewhat smaller and larger eggs respectively. All 12 regressions of totai egg volume on fish weight showed a common slope. However, there were significant differences in elevation of the regressions, with some of the stocks of trout producing up to a 55% greater volume of eggs. There appeared to be no relationship between the differences in egg number, size or total egg volume and the type or geograpfiical location of the farms on which the stocks were held. Although it remains to be determined to what extent these differences in reproductive performance are Inheritable, it is recommended that these characteristics should be taken into account by hatcheries in tbe design of long-term broodstock selection programmes for rainbow trout.

Globally, Anemia is one of the most prevalent disease. In developing countries women and children suffered more from anemia. Objective: To develop and explore the anti-anemic potential of iron enriched biscuits by using Bauhinia variegata leaves powder. Methods: Longitudinal study design was followed to check the therapeutic effect of Bauhinia variegata leaves powder biscuits in anemia-induced rats. For this purpose, dried powder of Bauhinia variegata leaves powder was prepared and functional biscuits were developed by utilizing Bauhinia variegata leaves powder and lemon juice. Thirty male anemia-induced albino rats were randomly divided into three groups G1 (standard diet), G2 (biscuits with 10 g Bauhinia variegata leaves powder) and G3 (biscuits with 10 g Bauhinia variegata leaves powder and 10 mL lemon juice). Feed intake, water intake, total body weight gain and hemoglobin levels of rats were determined after an interval of 15 day for study period of two months. The results obtained was statistically analyzed. Results: The results showed that functional biscuits prepared by using Bauhinia variegata leaves powder (high in iron) and lemon juice (rich in Vitamin C) significantly improved the feed intake, water intake, total body weight gain and hemoglobin levels of rats during 60 days study period. Conclusions: Conclusively, Bauhinia variegata leaves powder and lemon juice in combination are effective against anemia.

The consequences of avian egg‐size variation on offspring quality and survival remain unclear. We evaluated the effects of egg‐size and hatch‐date variation on survival of Lesser Scaup Aythya affinis ducklings in the wild. Duckling mass at hatching increased significantly with increasing egg size. Ducklings from larger eggs survived better than those from smaller eggs. We suspect that ducklings from larger eggs survived better because of advantages associated with larger or more efficient utilization of nutrient reserves, or both. We were unable to detect any within‐clutch differences in egg size of survivors and non‐survivors, nor any consistent direction in the difference in egg size between survivors and nonsurvivors within clutches. This suggests that within‐clutch variation may be insufficient to have survival consequences for offspring. In addition, ducklings that hatched later in the breeding season had a higher probability of survival. We suggest a food‐dependent hypothesis as an explanation for the seasonally increasing survival and for later nest initiation of Lesser Scaup compared with other North American ducks.

ObjectiveTo study the association between total and early pregnancy (<22 completed weeks) weight gain and risk of stillbirth, stratified by early‐pregnancy body mass index (BMI).DesignPopulation‐based cohort study.SettingStockholm‐Gotland Region, Sweden.PopulationPregnant women with singleton births (n = 160 560).MethodsPregnancy weight gain was standardised into gestational age‐specific z‐scores. For analyses of total pregnancy weight gain, a matched design with an incidence density sampling approach was used. Findings were also contrasted with current Institute of Medicine (IOM) weight gain recommendations.Main outcome measuresStillbirth defined as fetal death at ≥22 completed weeks of gestation.ResultsFor all BMI categories, there was no statistical association between total or early pregnancy weight gain and stillbirth within the range of a weight gain z‐score of −2.0 SD to +2.0 SD. Among normal‐weight women, the adjusted odds ratio of stillbirth for lower (−2.0 to −1.0 SD) and higher (+1.0 to +1.9 SD) total weight gain was 0.85 (95% CI; 0.48–1.49) and 1.03 (0.60–1.77), respectively, as compared with the reference category. Further, there were no associations between total or early pregnancy weight gain and stillbirth within the range of weight gain currently recommended by the IOM. For the majority of the BMI categories, the point estimates at the extremes of weight gain values (<−2.0SD and ≥2.0 SD) suggested protective effects of low weight gain and increased risks of high weight gain, but estimates were imprecise and not statistically significant.ConclusionWe found no associations between total or early pregnancy weight gain and stillbirth across the range of weight gain experienced by most women.Tweetable abstractThere was no association between weight gain during pregnancy and stillbirth among most women.

Understanding the selective pressures shaping the number of offspring per breeding event is a key area in the study of life-history strategies. However, in species with parental care, costs incurred in offspring production, rather than rearing, have been largely ignored in both theoretical and empirical studies until relatively recently. Furthermore, the few experimental studies that have manipulated production costs have not yet teased apart effects that operate via the parental phenotype from effects on the quality of the resulting young. To examine whether increased egg production influences parental brood rearing capacity independently of effects operating via egg quality, we experimentally increased egg production in gulls and then examined their capacity to rear a control clutch. We found that the capacity of parents to rear the control brood was substantially reduced solely as a consequence of having themselves produced one extra egg. The paradox that, in many species, parents apparently aim for fewer young per breeding event than the experimentally and theoretically demonstrated optimum, has partly arisen from the failure to take into account the constraints imposed by production costs.

The decorator crab, Microphrys bicornutus, is a common inhabitant of the turtle grass Thalassia testudinum. In order to establish the behaviour of a population of this species in an extreme shallow Thalassia complex (maximum depth less than 50 cm, and often exposed to the air), size distribution, population dynamics, reproductive effort and egg size were studied in Buchuaco—Venezuela. Monthly sampling was undertaken between June 1988 and December 1990. A total of 1403 specimens of M. bicornutus were captured. In each of the sampled years, size distribution was strongly skewed to the predominance of small size crabs. Females were significantly larger than males in all the three years. Small size and large size crabs showed periodic annual fluctuations in abundance, with peaks during the last months of the year for the first, and peaks between April and June for the latter. Medium size crabs showed no periodicity at all. Number of eggs per female ranged between 40 and 4305 (mean = 1067.4), and was positively correlated with female body size. Eggs increased their size gradually during their development, and differences in egg size between development stages were significant. The biological parameters found in this study are compared with other populations of this crab, found in Venezuela and Brazil, in different ecosystems. Results acquired in this work add new insights to the behaviour of this decorator crab, specifically on density variation and egg size (among others), living in an environment that is constantly exposed to air and to other physicochemical variations.

The Effect of Season of Maturity of the Laying Hen on Subsequent Egg Size at Periodic Intervals in the Laying Cycle

Intrauterine Growth and Infant Temperamental Difficulties: The Generation R Study

This study was conducted to investigate the effect of dietary inclusion of biochar and clay as feed additives on the growth performance and organ weight of broilers in a 56-day feeding trial. A total of ninety-six-day-old broilers (Ross 308) were fed diets containing biochar and clay. Treatments 1, 2, 3 and 4 were composed of T1(control), T2(5% biochar), T3 (5% clay) and T4 (2.5% biochar + 2.5% clay) in a completely randomized design having three replicates, each consisting of eight birds. The growth parameters were measured during the feeding trial and organ weight parameters were measured at the end of the experiment. The data collected were analyzed using one-way analysis of variance to determine the significant differences among the dietary treatments. The results showed that treatments were significantly (p &lt; 0.05) different in final body weight, total body weight gain, average daily body weight gain, total feed intake, average daily feed intake, feed cost per kg weight gain and kidney weight. Treatment 4 had the highest final weight value of 1.4067kg, highest total body weight gain of 1.3597kg, highest average daily body weight gain of 0.0242kg, highest total feed intake of 5.1097kg, highest average daily feed intake of 0.0910kg and highest feed cost of N3227.21. However, there were no significant (p &gt; 0.05) differences in initial body weight, feed conversion ratio, feed cost per kg body weight gain, heart, liver, pancreas, gizzard, spleen and lung weights. The results imply that inclusion of biochar and clay at 2.5% each in broiler diet can potentially increase growth performance.

Studies in Iceland (66°N) and Svalbard (78°N), combined with the results of previous work, allowed geographical comparisons of different aspects of the breeding biology of the Purple Sandpiper Calidris maritima, testing predictions that they may be related to latitude and altitude (here taken as surrogates for climatic severity). The breeding density was lowest in the polar deserts of Franz Josef Land (82°N) and highest in coastal Arctic Tern Sterna paradisaea colonies in Iceland where the terns perhaps afforded protection from predators. There was no difference in the percentages of 1‐year‐old (first‐year) birds in the breeding populations in Svalbard and Iceland. Time of breeding was related to both latitude and altitude, being later at higher latitudes and altitudes. In Iceland, larger males and males over 1 year old nested earlier than small males and 1‐year‐old males, respectively. Relaying occurred in Iceland but it was not observed in Svalbard. There were no geographical differences in clutch size. Egg size was related to female size in Svalbard. There were also geographical differences in egg size associated with female size (wing length), with the largest eggs in Iceland and smallest in south Norway. Males usually attended broods and the rates at which females deserted their broods were similar in Iceland and Svalbard. Chick growth rates were similar for Iceland and Franz Josef Land. Thus, in breeding biology, Purple Sandpipers varied geographically only in breeding density, time of nesting and egg size, which was associated with female size.

Reproduction in a Northern Population of Clemmys guttata

This study was conducted to investigate the effect of Achyranthes japonica root extract (AJE) added to a low-protein diet on broiler growth performance, nutrient utilization, cecal microbiota, and meat quality parameters. A total of 450 Ross 308 broilers were randomly assigned to one of five dietary treatments. The dietary treatments were standard crude protein (SCP) diet, low crude protein (LCP) diet, and LCP diet supplemented with 0.02, 0.04, and 0.06% AJE. Here, the SCP and LCP diets were 21.50% and 21.07% CP during days 8–21 and 20.00% and 19.40% CP during days 22–35, respectively. The LCP diet tended to decrease total body weight gain (TBWG) compared with the SCP diet. Increasing levels of AJE inclusion linearly increased ( P &lt; 0.05) TBWG and the LCP diet supplemented with AJE also increased ( P &lt; 0.05) TBWG compared with the LCP diet, whereas feed intake and feed conversion ratio were unaffected. AJE supplementation to the LCP diet tended to increase energy digestibility compared with the LCP diet. Breast muscle weight tended to increase by a graded level of AJE supplementation. In conclusion, AJE supplementation represented a potential ability to maintain a similar growth performance when added to a low-protein diet by enhancing nitrogen digestibility and meat quality in broilers.

Egg composition varies both within and between clutches, and mothers are expected to alter their deposition of resources to the egg depending on environmental conditions and breeding strategies. Within-clutch variation in egg composition has been proposed to reflect an adaptive maternal strategy influencing sibling competition. In species with brood reduction, mothers should reinforce brood hierarchies due to hatching asynchrony and favour senior chicks by making first-laid eggs larger, richer in nutrients, with higher testosterone and carotenoid levels and lower corticosterone concentrations than last-laid eggs [parental favouritism hypothesis (PFH)]. Moreover, mothers that are of better quality and/or experience better feeding conditions during laying are expected to increase their deposition of resources to the egg, resulting in differences between clutches [investment hypothesis (IH)]. Several components may act together to provide an optimal reproductive strategy, but studies of variation in different egg components in the same egg are relatively rare. We analysed egg size, testosterone and corticosterone concentrations and carotenoids measured as yolk colour between and within clutches for the facultative siblicidal Black-legged Kittiwake Rissa tridactyla. First-laid eggs were larger, contained lower testosterone, higher yolk colour score, and similar corticosterone levels than last-laid eggs. Thus, only differences in egg size and yolk colour supported the PFH. We used within-clutch egg size dimorphism as an indicator of the quality of the mother or the feeding conditions during laying. In support of the IH, we found that mothers of better quality or that experienced better feeding conditions deposited more corticosterone into their eggs. High corticosterone levels may benefit nestlings when there is no brood reduction but high sibling competition is present. We found no support for the hypothesis that egg components are mutually adjusted to each other and we discuss the possible reasons for this.