Individual Growth Performance Research Articles

Positive contribution of shoot apex to the growth and flooding tolerance of Hemarthria altissima upon complete submergence

ABSTRACT Flooding events tend to destroy the original flood-intolerant vegetation in riparian zones, but the flood-tolerant species can confront the stress, and contribute to the riparian ecosystem. Grass species, Hemarthria altissima, are usually dominant in the riparian zones. This species is considered as good forage which is usually grazed by livestock or mowed by local people. Therefore, the apical tissues of the plants are often removed, and the plants have to grow without stem apexes, during their life cycle. In this study, we aimed to examine the differences in growth performance of intact versus apex-cut individuals of H. altissima upon complete submergence. Two groups of H. altissima plants (with and without shoot apexes) were treated with dark non-submergence and dark complete submergence conditions for 200 days. During the experiment, we measured plant growth, biomass changes in plant organs, and the consumption of non-structural carbohydrates (NSC) by different tissues. During submergence, shoot elongation stopped, and around six lateral buds were developed averagely by each plant without apexes. This growth performance finally caused 60% decline of NSC in underground parts. The relatively intensive consumption of carbohydrates in submerged apex-removed plants induced the 21% stem length decreased under water, which indicated the decreasing submergence tolerance of plants with shoot apex removed. Therefore, we suggest that when using H. altissima for restoring degraded riparian ecosystems, the shoot apexes should be protected from grazing by livestock or harvesting by local people in order to maintain the submergence tolerance of H. altissima.

Effects of dietary addition of ellagic acid on rumen metabolism, nutrient apparent digestibility, and growth performance in Kazakh sheep.

Plant extracts have shown promise as natural feed additives to improve animal health and growth. Ellagic acid (EA), widely present in various plant tissues, offers diverse biological benefits. However, limited research has explored its effects on ruminants. This study aimed to investigate the effects of dietary addition EA on rumen metabolism, apparent digestibility of nutrients, and growth performance in Kazakh sheep. Ten 5-month-old Kazakh sheep with similar body weight (BW), fitted with rumen fistulas, were randomly assigned to two groups: the CON group (basal diet) and the EA group (basal diet + 30 mg/kg BW EA). The experiment lasted 30 days, and individual growth performance was assessed under identical feeding and management conditions. During the experimental period, rumen fluid, fecal, and blood samples were collected for analysis. The results indicated a trend toward increased average daily gain in the EA group compared to the CON group (p = 0.094). Compared with the CON group, the rumen contents of acetic acid and propionic acid were significantly increased in the EA group and reached the highest value at 2 h to 4 h after feeding (p < 0.05). Moreover, the relative abundances of specific rumen microbiota (Ruminococcaceae, uncultured_rumen_bacterium, unclassified_Prevotella, Bacteroidales, Bacteroidota, Bacteroidia, unclassified_Rikenellaceae, and Prevotella_spBP1_145) at the family and genus levels were significantly higher in the EA group (p < 0.05) compared to the CON group. The EA group exhibited significantly higher dry matter intake (p < 0.05) and increased the digestibility of neutral detergent fiber and ether extract when compared with the CON group (p < 0.05). Additionally, the plasma activities of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were significantly higher, while malondialdehyde (MDA) concentration was significantly lower in the EA group compared to the CON group (p < 0.05). In conclusion, dietary supplementation with 30 mg/kg BW EA in 5-month-old Kazakh sheep increased the dry matter intakQ16e, apparent digestibility of neutral detergent fiber, and ether extract, as well as the contents of acetic acid and propionic acid in rumen fluid. Moreover, EA supplementation regulated the ruminal microbiota, enhanced antioxidant capacity, and improved daily weight gain.

Использование экстракта Laminariacolax aecidioides при выращивании молоди африканского клариевого сома

An assessment was made of growth dynamics, hematological parameters of peripheral blood and changes in the structure of intestinal and liver tissues of juvenile African catfish Clarias gariepinus when an aqueous extract from the marine brown alga Laminariocolax aecidioides was included in the feed. Shown that the addition of an algal extract at a concentration of 5 % led to a significant improvement in the growth performance of individuals, which was expressed in an increase in growth rate, a decrease in the feed ratio and an increase in the fatness of fish. According to the results of hematological and histological studies, the extract of L. aecidioides contributed to the modulation of fish immunity by increasing the content of granulocytes (basophils and neutrophils) in the blood, as well as activation of the secretory function of the intestine (thickening of the lamina propria) and the immune function of the intestinal mucosa (increase in the size of goblet cells and an increase in the occurrence of clusters of eosinophilic and interepithelial cells). At the same time, the algae additive from L. aecidioides had virtually no negative effect on the histological picture of fish liver.

The responses of root functional traits of submerged plant &lt;i&gt;Vallisneria natans&lt;/i&gt; to substrate type and planting density and its relationship with individual growth performance

The responses of root functional traits of submerged plant &lt;i&gt;Vallisneria natans&lt;/i&gt; to substrate type and planting density and its relationship with individual growth performance

Strategic Training Practices and Firm Performance among Human Resource Management Consultancy Firms in Nairobi Kenya

Firm performance is essential for competitiveness, but many firms struggle with executing functional strategies, resulting in poor outcomes. In a dynamic market, strategic training is critical to maintaining superior performance, especially with growing global competition. Despite significant investments in employee training, the effect of strategic training on firm performance among HR consultancy firms in Nairobi, Kenya, remains underexplored. This paper aimed to examine the role of strategic training practices in firm performance. The study examined the effects of employee motivation to learn, the impact of perceived supervisor support and the effect of employee training attitudes on firm performance in HR consultancy firms. The study was grounded on learning organization theory. An explanatory research design was adopted, utilizing questionnaires to collect data from 185 human resource management consultancy firms in Nairobi. The data was analyzed using descriptive and inferential statistical methods to draw meaningful insights. The study highlighted the crucial role of strategic training and employee commitment in enhancing firm performance. Additionally, motivation to learn, supervisor support, and positive training attitudes showed strong positive correlations with performance in Nairobi’s HR consultancy firms. The regression analysis indicates these variables explain 2.3% of the variance in firm performance (R² = 0.023). The motivation to learn (β=0.079, p=0.009), supervisor support (β=0.128, p=0.022), and training employee attitude (β=0.196, p=0.013) were found to be statistically significant predictors of firm performance. In conclusion, strategic training practices such as motivation to learn, supervisor support, and employee attitudes significantly enhance firm performance. The study recommends that HR consultancy firms in Nairobi prioritize fostering employee motivation through continuous professional development and training. Strengthening supervisor support via leadership programs and promoting positive attitudes toward training, aligned with employee career goals, will enhance both individual growth and firm performance.

Divergent mechanisms of reduced growth performance in Betula ermanii saplings from high-altitude and low-latitude range edges

The reduced growth performance of individuals from range edges is a common phenomenon in various taxa, and considered to be an evolutionary factor that limits the species’ range. However, most studies did not distinguish between two mechanisms that can lead to this reduction: genetic load and adaptive selection to harsh conditions. To address this lack of understanding, we investigated the climatic and genetic factors underlying the growth performance of Betula ermanii saplings transplanted from 11 populations including high-altitude edge and low-latitude edge population. We estimated the climatic position of the populations within the overall B. ermanii’s distribution, and the genetic composition and diversity using restriction-site associated DNA sequencing, and measured survival, growth rates and individual size of the saplings. The high-altitude edge population (APW) was located below the 95% significance interval for the mean annual temperature range, but did not show any distinctive genetic characteristics. In contrast, the low-latitude edge population (SHK) exhibited a high level of linkage disequilibrium, low genetic diversity, a distinct genetic composition from the other populations, and a high relatedness coefficient. Both APW and SHK saplings displayed lower survival rates, heights and diameters, while SHK saplings also exhibited lower growth rates than the other populations’ saplings. The low heights and diameters of APW saplings was likely the result of adaptive selection to harsh conditions, while the low survival and growth rates of SHK saplings was likely the result of genetic load. Our findings shed light on the mechanisms underlying the reduced growth performance of range-edge populations.

Divergent Cross-Adaptation of Herbicide-Treated Wheat and Triticale Affected by Drought or Waterlogging.

Widely used agrochemicals that do not exert negative effects on crops and selectively target weeds could influence plant resilience under unfavorable conditions. The cross-adaptation of wheat (Triticum aestivum L.) and triticale (×Triticosecale Wittm.) exposed to two environmental abiotic stressors (drought and waterlogging) was evaluated after treatment with a selective herbicide (Serrate®, Syngenta). The ambivalent effects of the herbicide on the two studied crops were particularly distinct in waterlogged plants, showing a significant reduction in wheat growth and better performance of triticale individuals exposed to the same combined treatment. Histochemical staining for the detection of reactive oxygen species (ROS) confirmed that the herbicide treatment increased the accumulation of superoxide anion in the flooded wheat plants, and this effect persisted in the younger leaves of the recovered individuals. Comparative transcript profiling of ROS scavenging enzymes (superoxide dismutase, peroxidase, glutathione reductase, and catalase) in stressed and recovered plants revealed crop-specific variations resulting from the unfavorable water regimes in combination with the herbicide treatment. Short-term dehydration was relatively well tolerated by the hybrid crop triticale and this aligned with the considerable upregulation of genes for L-Proline biosynthesis. Its drought resilience was diminished by herbicide application, as evidenced by increased ROS accumulation after prolonged water deprivation.

Effects of dietary substitution of fishmeal by black soldier fly (Hermetia illucens) meal on growth performance, whole-body chemical composition, and fatty acid profile of Pontastacus leptodactylus juveniles.

Freshwater crayfish are considered as aquatic products of high quality and high nutritional value. The increasing demand has led to populations reduction in several locations throughout their range. Thus, the development of appropriate rearing conditions is considered necessary, among which, optimization of their diet is a basic part. Towards this direction, in the present study, a 98-day feeding trial was carried out to evaluate the impact of dietary fishmeal substitution by Hermetia illucens meal on Pontastacus leptodactylus juveniles kept under laboratory conditions. Insect meals represent an environmentally friendly alternative solution, considered as a high-value feed source, rich in nutrients such as protein and fat. Three dietary regimens were utilized with a fishmeal-based without Hermetia meal (HM) defined as the control diet (HM0), and two diets, the first with 50% (HM50) and the second with 100% (HM100) of fishmeal substitution by HM, respectively. Growth performance, whole-body composition, and fatty acid profiles of individuals were studied in the different treatments. At the end of the feeding trial, statistically significant differences were observed in the mean survival rate (SR), specific growth rate (SGR), feed conversion ratio (FCR) and weight gain (WG) values. More specifically, animals fed with HM-based diets had higher mean SR, while the control group performed better regarding FCR and SGR. The HM inclusion in the diet significantly altered the whole-body chemical composition of the crayfish signifying a different metabolic utilization compared to fishmeal (FM). The fatty acid analysis revealed that 16:0 (palmitic acid) was the predominant saturated fatty acid (SFA), 18:1ω9 (oleic acid) was found to be the main monounsaturated fatty acid (MUFA), while 18:2ω6 (linoleic acid) represented the major polyunsaturated fatty acid (PUFA) followed by C20:3 cis ω3 (cis-11-14-17-eicosatrienoate) and C22:6 cis ω3 (cis-4,7,10,13,16,19-Docosahexaenoic) fatty acids. The inclusion of dietary HM significantly reduced the contents of ∑SFAs, ∑PUFAs and ∑ω6 fatty acids, as well as those of C22:6 cis ω3 and increased the ω6/ω3 and hypocholesterolemic to hypercholesterolemic ratios in the body. In parallel with improvements in balanced diets and in culture conditions that need to be optimised for rearing of freshwater crayfish, our study provides new data that enlighten the suitability of insect meals in the nutrition of P. leptodactylus.

The effect of amylase supplementation on individual variation, growth performance, and starch digestibility in broiler chickens

The objective of this study was to evaluate the variance of starch digestibility in broilers individually fed diets without or with supplemental exogenous amylase. A total of 120 d-of-hatch male chicks were individually reared from 5 to 42 d in metallic cages and fed maize-based basal diets or diets containing 80 kilo-novo-α-amylase units/kg (60 birds or replicates per treatment). Beginning on d 7, feed intake, body weight gain, and feed conversion ratio were recorded; partial excreta collection was conducted every Monday, Wednesday, and Friday until 42 d, when all birds were sacrificed for individual collection of duodenal and ileal digesta. Lower feed intake (4,675 vs. 4,815 g) and feed conversion ratio (1.470 vs. 1.508) were observed in amylase-fed broilers during the overall period (7-43 d; P < 0.01), whereas body weight gain was not affected. Amylase supplementation improved total tract starch (TTS) digestibility (P < 0.05) on each day of excreta collection (except for d 28, where no difference was found), averaging 0.982 vs. 0.973 compared to basal-fed broilers from d 7 to 42. Both apparent ileal starch (AIS) digestibility and apparent metabolizable energy (AMEN) were increased (P <0.05) from 0.968 to 0.976 and from 3,119 to 3,198 kcal/kg, respectively, with enzyme supplementation. Activity of amylase in the duodenum was higher (18.6 vs. 50.1 IU/g of digesta) in supplemented birds. Amylase supplementation led to a reduced coefficient of variation for both TTS (averaged 2.41 vs. 0.92% from 7 to 42 d) and AIS digestibilities (1.96 vs. 1.03%), as well as AMEN (0.49 vs. 0.35%), when compared to the nonsupplemented group, indicating lower individual heterogenity. An age effect was detected for TTS digestibility, as both groups saw an increase during the first weeks (slightly more pronounced in the supplemented group); older birds (d 30 onwards) presented a lower TTS digestibility compared to ages between 7 and 25 d. In conclusion, amylase supplementation in maize diets for broilers can attenuate individual bird variation for starch and energy utilization by increasing amylase activity and enhancing starch digestibility.

Growth Rate and Sexual Performance of Domesticated Blue Swimming Crab, Portunus pelagicus (Linnaeus, 1758) in Earthen Ponds

It is generally accepted that using domesticated aquatic animal is advantageous due to their adaptation to a captive environment. Despite previous reports on the domestication of the blue swimming crab, Portunus pelagicus (Linnaeus 1758), empirical data are lacking on the growth and sexual performance of domesticated individuals of this crab species. Thus, the growth and sexual performance were evaluated of domesticated P. pelagicus from the 1st to the 3rd generations. Domesticated crabs in the 1st (G1), 2nd (G2) and 3rd (G3) generations were reared for 150 days in 400 m2 earthen ponds at a density of 2 crabs/m2. Each generation had 3 replicates. The performance results showed that the mean final CW (11.4 cm) of G1 was higher than in G3 (9.9 cm), and G1 had a higher mean final BW (123.4 g) and SGR (4.8 % day–1) than in G2 (108.2 g and 4.7 % day–1, respectively) and G3 (102.9 g and 4.7 % day–1, respectively). The mean SR values in G1 (20.2 %), G2 (18.8 %) and G3 (18.3 %) were not significantly different. No significant differences were observed in mean FCR and productivity in G1 (5.8 and 94.1 kg/pond, respectively), G2 (6.6 and 82.9 kg/pond, respectively) and G3 (6.7 and 82.0 kg/pond, respectively). Sexual dimorphism in G1, G2 and G3 was observed at 60 days of rearing, with the sex ratio being 1:1 in each generation and 5.6 and 6.7 % of female crabs in G2 and G3, respectively, being berried in this period. In contrast, the berried females in G1 (17.6 % of females) were 1st found on day 90 of the rearing period. At day 150, the percentage composition ranges for yellow, brown and dark gray egg colors of the reared berried female crabs were 20.0 - 25.0, 40.0 - 50.0 and 25.0 - 40.0 %, respectively. These finding should assist in the future establishment of a selective breeding program that produces the 1st genetically improved strain of P. pelagicus possessing desired traits such as fast growth and high survival rates.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Currently, the culture techniques for blue swimming crab (Portunus pelagicus) have not yet been fully established to expand the farms and increase productivity to a commercial scale&#x0D; It is generally accepted that using domesticated broodstock is advantageous due to their adaptation to a captive environment&#x0D; Successful aquaculture of P.pelagicus should rely on domesticated broodstock in which domestication improves reproductive and growth performances&#x0D; &#x0D; GRAPHICAL ABSTRACT

Dietary benzoic acid and supplemental enzymes alter fiber-fermenting taxa and metabolites in the cecum of weaned pigs.

Inclusion of enzymes and organic acids in pig diets is an important strategy supporting decreased antibiotic usage in pork production. However, limited knowledge exists about how these additives impact intestinal microbes and their metabolites. To examine the effects of benzoic acid and enzymes on gut microbiota and metabolome, 160 pigs were assigned to one of four diets 7 days after weaning: a control diet or the addition of 0.5% benzoic acid, 0.045% dietary enzymes (phytase, β-glucanase, xylanase, and α-amylase), or both and fed ad libitum for 21 to 22 d. Individual growth performance and group diarrhea incidence data were collected throughout the experimental period. A decrease of 20% in pen-level diarrhea incidence from days 8 to 14 in pigs-fed both benzoic acid and enzymes compared to the control diet (P = 0.047). Cecal digesta samples were collected at the end of the experimental period from 40 piglets (n = 10 per group) and evaluated for differences using 16S rRNA sequencing and two-dimensional gas chromatography and time-of-flight mass spectrometry (GCxGC-TOFMS). Analysis of cecal microbiota diversity revealed that benzoic acid altered microbiota composition (Unweighted Unifrac, P = 0.047, r2 = 0.07) and decreased α-diversity (Shannon, P = 0.041; Faith's Phylogenetic Diversity, P = 0.041). Dietary enzymes increased fiber-fermenting bacterial taxa such as Prevotellaceae. Two-step feature selection identified 17 cecal metabolites that differed among diets, including increased microbial cross-feeding product 1,2-propanediol in pigs-fed benzoic acid-containing diets. In conclusion, dietary benzoic acid and enzymes affected the gut microbiota and metabolome of weaned pigs and may support the health and resolution of postweaning diarrhea.

Inclusive talent development as a key talent management approach: A systematic literature review

Over the past decades, organizations have faced challenges in retaining good employees due to market competition and talent scarcity, thereby forcing leaders to improve their human resource strategies. Organizations often source exclusive talent development instead of nurturing talent inclusively. Exclusive refers to organizations' tendency to hire top talents outside their organization when needs arise, or if they have to look for candidates within the organization, only those identified as performers within their elite pool are selected. Literature suggests that inclusive talent development (i.e., career development via training for all employees regardless of individual performance) can complement management for employee retention. The present study carries out a systematic review of articles published from 1997 to 2020 pertaining to talent development, particularly inclusive nurturing, to enable frugal human resource management, i.e., developing human resource inclusive talent development (ITD) in a resource constrained environment. We address three major questions: to what degree is talent development (TD) represented in the wider talent management (TM) literature?; how does ITD contribute to individual talent growth and organizational performance?; and what are the limitations of current research on ITD? A total of 48 articles on TD, with 13 articles on ITD, are analyzed to provide theoretical and practical insights. This review presents research gaps on inclusive TD, and highlights future research directions, such as wider coverage to develop a more comprehensive scope, TD for low performers to improve their individual growth and organizational performance, application of frugal innovation through ITD, and association with resource-based view – valuable, rare, inimitability, and organized model (RBV-VRIO). While ITD coupled with other TM activities has significant effect on individual growth and organizational performance, the evidence for and discussion of this concept remains scarce. The research contributes to existing HRM literatures: (1) TD is a limited area of research and has minority representation within TM literature; (2) ITD is becoming increasingly crucial for individual talent growth and organizational performance towards a sustainable competitive advantage as primed by the RBV – VRIO model; and (3) key limitations of research on TD include one-sided perspectives to TD, lack of balance between individual talent growth and organizational performance, and other methodological weaknesses.

Effect of sea surface temperature on the growth performance of the thread herring Opisthonema libertate (Günther, 1868) in the southern Gulf of California

The present study assessed the effect of sea surface temperature (SST) on the individual growth performance of the thread herring Opisthonema libertate in the southern Gulf of California. For the period from 1988 to 2017, based on monthly length-frequency information, the von Bertalanffy equation's growth parameters (L∞, K, and t0) were estimated annually. Annual values of the growth performance index Φ' were inversely related to the SST (P &lt; 0.05). The values of K and L∞ corresponding to the modal value of the distribution of Φ' were taken as representative of the species, and the temperature change pattern function over time was incorporated as a forcing of the growth coefficient, K, in the growth model. Thus, it was possible to represent the yearly effect of SST on growth performance. These estimates are considered of great interest for future research because they directly influence the variability in allocating the number of individuals at different ages.

Heritability and genetic correlation estimates of semen production traits with litter traits and pork production traits in purebred Duroc pigs.

We estimated heritabilities of semen production traits and their genetic correlations with litter traits and pork production traits in purebred Duroc pigs. Semen production traits were semen volume, sperm concentration, proportion of morphologically normal sperms, total number of sperm, and total number of morphologically normal sperm. Litter traits at farrowing were total number born, number born alive, number stillborn, total litter weight at birth, mean litter weight at birth, and piglet survival rate at birth. Litter traits at weaning were litter size at weaning, total litter weight at weaning, mean litter weight at weaning, and piglet survival rate from birth to weaning. Pork production traits were average daily gain, backfat thickness, and loin muscle area. We analyzed 45,913 semen collection records of 896 boars, 6,950 farrowing performance records of 1,400 sows, 2,237 weaning performance records of 586 sows, and individual growth performance records of 9,550 animals measured at approximately 5 mo of age. Heritabilities were estimated using a single-trait animal model. Genetic correlations were estimated using a 2-trait animal model. Estimated heritabilities of semen production traits ranged from 0.20 for sperm concentration to 0.29 for semen volume and were equal to or higher than those of litter traits, ranging from 0.06 for number stillborn and piglet survival rate at birth to 0.25 for mean litter weight at birth, but lower than those of pork production traits, ranging from 0.50 for average daily gain to 0.63 for backfat thickness. In many cases, the absolute values of estimated genetic correlations between semen production traits and other traits were smaller than 0.3. These estimated genetic parameters provide useful information for establishing a comprehensive pig breeding scheme.

Disentangling patterns in population parameters of the wedge clam Donax hanleyanus from sandy beaches of Argentina: The role of environmental variability

The concurrent role of morphodynamics and estuarine gradients in shaping population patterns in sandy beach macrofauna has not been adequately assessed. Here, we analyze the effects of beach morphodynamics, salinity, sea surface temperature, and chlorophyll-a (chl-a) on life-history traits of the wedge clam Donax hanleyanus in four sandy beaches located along the estuarine gradient generated by the Río de la Plata (RdlP, Argentina) over a 13-month period. A general linear model showed that chl-a and salinity were positively correlated with the abundance of D. hanleyanus, whereas between-beach differences in individual size, population structure, and growth performance were mainly explained by salinity fluctuations. These results indicate that the estuarine gradient of the RdlP plays a critical role in shaping life-history traits, population structure, and abundance of D. hanleyanus at local to regional scales, overriding the effects of local characteristics of the habitat. The study highlights the importance of conducting multi-scale studies that integrate environmental factors to elucidate the main physical drivers of population patterns in sandy beach ecosystems.

Effects of harvest intensity on the marketable organ yield, growth and reproduction of non-timber forest products (NTFPs): implication for conservation and sustainable utilization of NTFPs

BackgroundNon-timber forest products (NTFPs) are an important part of forest biodiversity, and the subsistence and trade of local people, especially in less developed countries. Because of the high ecological and economic value, NTFPs have faced the problem of over-exploitation, and the key to solve this problem is to determine the feasible way of sustainable utilization of NTFPs. Harvest intensity is one of the most important and easily controlled utilization factors, which can greatly influence the plant individual survival, growth and reproductive performances, and even the population structure and dynamics. Therefore, we chose two common and important NTFPs species with different marketable parts (i.e., Acanthopanax senticosus with tender leaves and Aralia elata with tender buds) as our study objects. Aiming to determine the optimum harvest intensity for sustainably utilizing both NTFPs species, five levels of harvest intensity treatments (i.e., control, light, medium, high and severe) were designed to assess the effects of harvest intensity on their marketable organ yield, plant growth and reproductive performances.ResultsThe biomass growth rates of marketable organ and plant growth of A. senticosus under light harvest intensity treatment were significantly higher than those under other harvest intensities. The plant height growth and 1000-seed weight of A. elata under severe harvest intensity treatment were significantly lower than those under control treatment.ConclusionsThe light harvest intensity with 25% leaf removal and the high harvest intensity with all terminal buds harvested are the optimum harvest intensity to maintain the sustainable utilization of A. senticosus and A. elata, respectively. These findings could provide managers with basic but practical guidance for making decisions about the sustainable harvest management plan for the cultivated NTFPs species, and further provide a theoretical basis for managers to establish the harvest regulations for wild NTFPs species. Consequently, the local residents or communities can improve their income while ensure the sustainable development of wild NTFPs.

Temperature induced changes in physiological traits and expression of selected candidate genes in black tiger shrimp (Penaeus monodon) larvae

Temperature is an important abiotic factor influencing growth, development, metabolic performance and sex determination of aquatic organisms. The present study was conducted to test the effect of six different temperature levels (24℃, 26℃, 28℃ as control, 30℃, 32℃ and 34℃) on the physiological (growth, developmental durations, survivability, sex ratios and O2 consumption) and genetic (changes in expression pattern of seven candidate genes: three male sex determining genes, three female sex determining genes and a single thermal stress response gene) aspects of black tiger shrimp (Penaeus monodon) larvae. Temperature treatments significantly altered the growth performance of shrimp individuals (P < 0.05) with the highest growth performance obtained at 32℃, moderate levels were obtained at 28−30℃ and the lowest levels were obtained at the remaining temperatures. Temperature treatments significantly shortened the larval developmental durations at 28℃, 30℃ and 32℃ (required 44–46 days for sex differentiation) while 52–63 days were required at 24℃, 26℃ and 34℃. Temperature treatments also altered sex ratios of experimental P. monodon individuals; significantly higher (P < 0.05) proportions of males (coupled with higher expression levels of male sex determining genes) were obtained at lower temperatures (24℃ and 26℃) while larger proportions of females (with higher expression levels of female sex determining genes) were obtained at higher temperature levels (30℃, 32℃ and 34℃). The thermal stress response gene, heat shock protein (HSP70) showed constant expression levels at 28℃ but higher expression levels were obtained at other temperatures. Results imply that higher temperature can significantly increase the expression of female sex determining genes to produce larger proportions of females in P. monodon that in turn can help to improve aquaculture production.

Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth performance of cow-calf pairs grazing native range.

Crossbred Angus cow–calf pairs (n = 28 pairs) at the Central Grasslands Research Extension Center (Streeter, ND) were used to evaluate an electronic feeder to monitor individual mineral intake and feeding behavior and their relationship with growth performance and liver mineral concentrations. Cows and calves were fitted with radio frequency identification ear tags that allowed access to an electronic feeder (SmartFeed system; C-Lock Inc., Rapid City, SD) and were provided ad libitum minerals (Purina Wind and Rain Storm, Land O’Lakes, Inc., Arden Hills, MN). Mineral intake, number of visits, and duration at the feeder were recorded over a 95-d monitoring period while pairs were grazing native range. Liver biopsies were collected from a subset of cows on the final day of monitoring and analyzed for mineral concentrations. Data were analyzed with the GLM procedure in SAS for mineral intake and feeding behavior with age class (cows vs. calves), intake category (high vs. low), and the interaction between class and category in the model. Correlations were calculated among cow feeding behavior and calf intake and growth performance with the CORR procedure, and a comparison of liver mineral concentrations among cows of high (>90 g/d; average 125.4 g/d) and low (<90 g/d; average 33.5 g/d) mineral intake was performed using the GLM procedure. High-intake calves (>50 g/d; average 72.2 g/d) consumed greater (P < 0.001) amounts of minerals than low-intake calves (<50 g/d; average 22.2 g/d) intake calves. Cows and calves attended the mineral feeder a similar (P = 0.71) proportion of the days during the experiment (overall mean of 20%, or once every 5 d). On days calves visited the feeder, they consumed less (P < 0.01) minerals than cows (222 ± 27 vs. 356 ± 26 g/d, respectively). Over the grazing period, calves gained 1.17 ± 0.02 kg/d, whereas cows lost 0.35 ± 0.02 kg/d. Calf mineral intake was correlated with cow duration at the mineral feeder (r = 0.403, P = 0.05). Cows with high mineral intake had greater (P < 0.01) concentrations of Se (2.92 vs. 2.41 ug/g), Cu (247 vs. 116 ug/g), and Co (0.51 vs. 0.27 ug/g) compared with low mineral intake cows, but liver concentrations of Fe, Zn, Mo, and Mn did not differ (P ≥ 0.22). We were able to successfully monitor individual mineral intake and feeding behavior with the electronic feeder evaluated, and the divergence in mineral intake observed with the feeder was corroborated by concentrations of minerals in the liver.

Boylamanın ve Farklı Boy Kompozisyonlarında yetiştirilmesinin Melez Tilapia (Oreochromis niloticus ♀ X Oreochromis aureus♂) Yavrularının Büyüme Performansları Üzerine etkisi

Su ürünleri yetiştiriciliğinde boylama uygulaması balıklar arasında oluşan boy farkının yarattığı dezavantajlardan korunmak amacıyla yapılır. Bu etkinlikle büyük ve küçük bireyler besleme periyodu sırasında birbirlerinden ayrılırlar. Bu amaçla kurgulanan bu araştırmada Oreochromis niloticus♀ x Oreochromis aureus♂ melezlerinin yetiştiriciliğinde küçük bireylerin büyüme ve besi performansları üzerine sürüye eklenen büyük bireylerin etkilerinin olup olmadığının belirlenmesi amaçlanmıştır. Denemede 0 yaş 1 ile 4 g‘lık melez yavrular fiber tanklara 40 adet/m3 oranında stoklanmış ve 75 gün boyunca yetiştirilmiştir. Deneme grupları, tamamı 1 g‘lık küçük bireylerden oluşan boylanmış bir grup (G1), 1 g ve 2g‘dan oluşan (G2), 1 g ve 3g‘dan oluşan (G3) ve 1 g ve 4g‘dan oluşan (G4) grubundan oluşmuştur. Çalışma sonunda boylamanın tilapia melezlerinin büyümesine pozitif etki etmediği görülmüştür. Buna karşı içinde büyük bireylerin bulunduğu G2 grubundaki küçük bireylerin (18,60±0,33g) diğer gruplardaki küçük bireylerden daha iyi büyüdüğü ortaya çıkmıştır. Bununla birlikte G2 grubu diğer gruplardan daha iyi bir (1,39±0,05) YDO‘na ulaşmıştır. En iyi ekonomik dönüşüm oranı yine G2 grubunda (11,12±0,75) elde edilmiştir. Sonuç olarak farklı boydaki bireylerle yapılan yetiştiricilik uygulamasının melez tilapia yavrularının gelişimine pozitif etki yarattığı, özellikle 1+2 g şeklinde stoklandıklarında rekabet ortamının geliştiği ve bu durumun yetiştiricilik ekonomisine olumlu yönde etki ettiği gözlemlenmiştir.

Multiphasic nonlinear mixed growth models for laying hens

Appropriate evaluation of BW and gain during rearing is required for optimal extended laying performance in laying hens. The objective of this study was to compare monophasic, diphasic, and triphasic Gompertz and logistic models describing BW and gain in individually fed free-run laying hens and to study the variation between individuals in shape parameters. Fifteen Lohmann Brown Lite hens were fed ad libitum from week 0 to 43 with a precision feeding system, measuring feed intake and BW individually in a group housed setting. Random variables related to mature weight and timing of maximum gain during the pubertal growth phase were introduced into the multiphasic model for BW with the best fit. For both the weight-age and gain-age functions, the diphasic and triphasic Gompertz and logistic model models fitted the data better than the monophasic models. The Gompertz model was able to identify the ages at the highest gain at similar time points for both BW and gain, whereas the logistic models failed to do so. The derivative of the multiphasic Gompertz models for the gain-age relationship identified age at the highest gain at similar ages as compared with the logistic models for gain. The mixed models predicted that the individual mature BW ranged from 1.83 kg to 2.10 kg and the variability in the timing of the highest rate of gain during the pubertal growth spurt ranged from 15.26 wk to 19.79 wk. Including random terms associated with the mature BW and the second inflection point of the diphasic Gompertz growth model allowed for identification of variability in the growth curve shape between individuals, which can be a tool to study the relationship between the individual growth curve shape and performance parameters.