Effects of different levels of energy and protein sources on the growth performance, feeding, survival rate and the chemical body composition of juvenile Pacific white shrimp (Litopenaeus vannamei)

The present study was carried out in order to establish an economical effective diet for the pacific white shrimp in the southern part conditions of Iran. With the consideration of three dietary energy levels (E1=262, E2=312, E3=362 kcal 100 g-1 diet) and six ratios of fish meal (FM) to soybean meal (SBM) [(P1=100%FM+0%SBM, P2=80%FM+20%SBM, P3=60%FM+40%SBM, P4=40%FM+60%SBM, P5=20%FM+80%SBM, P6=0%FM+100%SBM)], 18 experimental diets (with 36% crude protein) were prepared. Completely randomized design was used to assign 54 polyethylene 300 litre round tanks provided by aeration and flow through water system and was stocked by 19 juvenile as 3 replicates to each treatment. Shrimps average weight was about 0.77 grams at the start. After 56 days culture period, maximum growth and nutritional performances were observed in the P6E1 treatment (containing 100% soybean meal and 262 kcal 100 g-1 diet) and P5E1 treatment (containing 80% soybean meal and 262 kcal 100 g-1 diet). Also the highest survival rate of the shrimps was observed in the P1E1, P1E2, P3E3 and P5E3 treatments. Additionally interactive effect of different protein ratios and energy levels had significant difference on body protein, fat, fiber and ash contents (P<0.05). Results of the present study suggest the possibility replacement of at least 80% of dietary fish meal by soybean meal in the diet of pacific white shrimp in the conditions of southern part of Iran.

Study on some biological and feeding factors of spined loach Cobitis taenia from the Babolrud, Talar and Siahrud Rivers

Spined loach, Cobitis taenia, is a predominant fish in the river systems of the southern Caspian Sea basin. Although there is evidence of the geographical divergence of this taxon, but no information is available on morphological differences within the species populations. This study was designed to evaluate some biological factors including; morphometric and meristic characters, length-weight, age-growth, condition factor, diet, reproduction, variation and differentiation, in the Babolrud, Talar and Siahrud Rivers in south of the Caspian Sea basin. Age, sex ratio, fecundity, ova diameter and gonadosomatic index were estimated. Also, regression analyses was tested the relation between fecundity and fish length, weight, gonad weight, and also age. Totally 858 fish of which 721 were matures, were collected from these rivers by electrofishing. 37 morphometric characters, 9 meristic characters and 78 truss network system characters were estimated. Resulats of DFA analysis based on data of morphometric and meristic showd that these populations are highly (94.5%) varios from each other. In discriminate function analysis, the proportion of individuals correctly classified into their original groups was 61%, 65.4% and 86.5% for upstream and downstream, respectively. Clustering based on Euclidean distances among groups of centroids using an UPGMA and also principal component analysis’ results for morphometric data indicated that these populations from these three rivers were clearly distinct from each other. Regression equations between length and weight in these three populations were significantly different from Folton factor (b=3), that showed the fish has a negative Alometric growth process. Condition factor was estimated between 0.8912 to 1.2736 and 0.8131 to 1.4489 for males and females, respectively. Sex ratio (female: male) in these populations was 1.2816:1. The difference between the number of females and males was significant and females were more than males. The female and male specimens reach maturity by Tl more than 40 and 30 mm and at the age of 2+ and 1+, respectively. The mean of ova diameter was 0.5824±0.2882. The spawning took place from May to late July, at the water temperature from 18.7 to 24.0°C. The GSI values average at the beginning of the reproduction period was about 9%, with ranged from 2 to 26% in ripe mature females. The absolute and relative fecundity were 2109±792 and 579±208 respectively. The absolute fecundity was significantly related to body weight and gonads weight. Based on the pattern of gonado-somatic index, it was concluded that this fish has prolong active reproductive period, which is a type of adaptation by short-lived small fishes to environmental conditions. The macroscopic and histological results showed that the female and male have 5 and 4 stages in their maturation process, respectively. The RLG index was about 0.4732, which showed the fish is a carnivorous species. Significant difference was observed between fishes with different length and diet. The main foods of the fish were Trichoptera, Chironomidae larvae and Ephemeroptera which were their prefered food as well, however it was estimated that the food selection and diet are affected by environmental conditions.

Study on effects of extracted probiotics from microbial flora of digestive system on growth indices in beluga (Huso huso) and Persian sturgeon (Acipenser persicus)

Isolation of Lactic Acid Bacteria (LAB) was carried out from gastro intestinal tract of beluga and Persian sturgeon at international sturgeon research institute and PCR has been used for bacteria Identification. Two species of LAB including Enterococcus seriolicida and Leuconostoc mesenteroides were isolated from Gastrointestinal tract (GI) of persian sturgeon in this study and the counts of Leu. mesenteroides (4.63×102 CFU/gr of GI) was significantly higher than other species. Lactobacillus curvatus, Lactococcus raffinolactis, Lactococcus lactis and Streptococcus sp. were also isolated from GI of beluga and maximum counts was belonged to Lb. curvatus (4.63×102 CFU/gr of GI) in this species. Dominant species were lyophilized and adding to the water since start of mix feeding of sturgeon with different counts including 2×109, 5×109 and 9×109 CFU/gr of live food, 4 times a day. The results revealed that the maximum and minimum growth rate and protease, amylase, and lipase activity in beluga was gained by using of Lb. curvatus with total viable count of 9×10 9 CFU/gr of live food and Leu. mesenteroides with total viable count of 9×109 CFU/gr of live food. According to the results of this study, the maximum and minimum growth rate and protease, amylase, and lipase activity in Persian sturgeon was gained by using of Leu. mesenteroides with total viable count of 2×10 9 CFU/gr of live food and Lb. curvatus with total viable count of 9×109 CFU/gr of live food. Histological study showed that gastrointestinal development was same during larva rearing in control and other treatments but the size of liver was bigger in treatments that received nonspecific LAB in both species. According to the results, positive effects of using dominant specific LAB bacteria for larviculture of sturgeon has been proved in this study.

Notes on growth and feeding of Crocodilus niloticus

The Uganda Fisheries Department had for some time, kept Nile crocodiles in captivity, and had thus collected a considerable amount of data on growth and feeding rates. It had also devised marking and handling techniques, and a system of pens and enclosures to deal with crocodiles up to 3 m. long. The following account describes these techniques and results, which followed a study of a proposed commercial crocodile farm.

Early ontogeny of Ancherythroculter nigrocauda and effects of delayed first feeding on larvae

Development of embryos and larvae in Ancherythroculter nigrocauda Yih et Woo (1964) and effects of delayed first feeding on larvae were observed after artificial fertilization. The fertilized eggs were incubated at an average temperature of 26.5 degrees C (range: 25.7-27) and the larvae reared at temperatures ranging from 21.8 to 28 degrees C. First cleavage was at 50 min, epiboly began at 7 h 5 min, heartbeat reached 72 per min at 24 h 40 min and hatching occurred at 43 h 15 min after insemination. Mean total length of newly hatched larvae was 4.04 +/- 0.03 mm (n = 15). A one-chambered gas bladder was observed at 70 h 50 min, two chambers occurred at 15 days, and scales appeared approximately 30 days after hatching. Larvae began to feed exogenously at day 4 post-hatch at an average temperature of 24 degrees C. Food deprivation resulted in a progressive atrophy of skeletal muscle fibres, deterioration of the larval digestive system and cessation of organ differentiation. Larval growth under food deprivation was significantly affected by the time of first exogenous feeding. Starved larvae began to shrink, with negative growth from day 6 post-hatch. The point of no return (PNR) was reached at day 11 after hatching. Mortality of starved larvae increased sharply from day 12 after hatching.

Effect of feeding strategy and carbohydrate source on carbohydrate utilization by white sturgeon (Acipenser transmontanus) and hybrid tilapia (Oreochromis niloticus X O-aureus)

Two 8-week growth trials were conducted to determine the effect of continuous (CF) versus 2 meals day(-1) (MF) feeding and 30% starch versus 30% glucose diets on the carbohydrate utilization of 9.0-g white sturgeon and 0.56-g hybrid tilapia. The two trials were conducted under similar conditions except that sturgeon were kept at 18.5 degrees C in a flow-through system and tilapia were kept at 26 degrees C in a recirculating system. Significantly (P less than or equal to 0.05) higher specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER), body lipid content and liver glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activities were observed in the CF than MF sturgeon. Only SGR, FE and PER were higher in sturgeon fed the starch than the glucose diets. Only higher liver G6PDH and malic enzyme (ME) activities were observed in the CF than MF tilapia but higher SGR, FE, PER and liver G6PDH, 6PGDH and ME activities were observed in tilapia fed the starch diet than those fed the glucose diet. This suggested that carbohydrate utilization by sturgeon was more affected by feeding strategy whereas tilapia was more affected by carbohydrate source. Furthermore, white sturgeon can utilize carbohydrates better than hybrid tilapia regardless of feeding strategy and carbohydrate source.

Dynamic changes of total bacteria and Vibrio in an integrated seaweed-abalone culture system

Polyculture of seaweeds alongside fed animal aquaculture is an environmentally friendly means of avoiding eutrophication problem both in land-based and sea-based monoculture systems. Many aspects of such polyculture systems have been described, but little attention has been given to the impact of live seaweeds on the microbiological properties of the water that connects the algae and animals. In this investigation, the Pacific red alga Gracilaria textorii was cultured in a recirculated dual tank system (150 L) with the juvenile abalone Haliotis discus hannai. Dynamic changes of total bacteria (TB) and total Vibrio (TV) in the water of polyculture and monoculture systems were evaluated. Results revealed that (1) level of TB in the polyculture was constantly higher than in the monoculture over a 6.5-day period. While levels of TV in the polyculture was detected to be constantly lower than in the monoculture, (2) integration of G. textorii in the abalone culture changed the Vibrio compositions in the water as judged by the changes of bacteria colony types; (3) application of artificial diet led to dramatic increase of the levels in TB and TV in both systems at 12 h after application in the 24-h test and resulted in selective propagation of Vibrio in the water in the monoculture system; (4) polyculture of G. textorii with juvenile abalone in combination with feeding with live algal diet helped to maintain low levels of TV and the balance of the Vibrio composition; (5) living biomass of G. textorii was effective in preventing propagation of two purified Vibrio strains (V alginolaticus and V logei) in the water. These results provide a general basis of the dynamic changes of levels in TB and TV in a seaweed-abalone polyculture system with or without artificial diet in tanks. (c) 2005 Elsevier B.V All rights reserved.

Effects of delayed first feeding on growth and survival of rock bream Oplegnathus fasciatus larvae

The effects of the timing of first feeding (0, 1 and 2 days after yolk exhaustion) and starvation on the point-of-no-return (PNR), survival and growth of laboratory-reared rock bream larvae were studied under controlled conditions. Larvae began to feed exogenously at 3 days after hatching (dah) and reached PNR on 54 h after yolk exhaustion at 22 +/- 1.5 degrees C. Larvae growth was significantly affected by the time of first exogenous feeding. The growth of 0 day delayed first feeding larvae was obviously faster than those of the other delayed first feeding larvae (P<0.05) whether at 7 dab (SL=3.40 mm, SGR=5.7, CV=4.0) or at 15 dah (SL=4.85 mm, SGR=6.1, CV=8.2) with a more uniform size distribution. Survival of 0 day delayed first feeding larvae and I day delayed first feeding larvae was 13% and 8% at the end of experiment, respectively, while no larvae survived up to 7 dah for 2 days delayed first feeding larvae and unfed larvae. Food resulted in a progressive deterioration of the larval digestive system and atrophy of skeletal muscle fibre. The ratios of head length to SL (standard length), body height to SL and eye diameter to SL were the most sensitive morphometric indices to detect the effects of fasting on larval condition. Present results showed that the combination of morphological and morphometric variables could be used to evaluate the nutritional condition of rock bream larvae. In order to avoid the potential mortality and gain better development, survival and growth in industrial production, the rock bream larvae must establish successful first feeding within 2 days after yolk exhaustion. (C) 2008 Elsevier B.V. All rights reserved.

The adaptive significance and prevalence of courtship feeding in Hawaiian swordtail crickets

Males of many insect species feed their partner during courtship and mating. Studies of male nutrient donation in various systems have established that nuptial feeding has evolved mostly through sexual selection. Although there is extensive diversity in form, the function of nuptial gifts is typically limited to either facilitating copulation or increasing ejaculate transfer, depending on the time at which the gift is consumed by females. Unlike other insects, the Hawaiian swordtail cricket Laupala (Gryllidae: Trigonidiinae) exhibits serial transfer of nuptial gifts. Males transfer multiple spermless 'micro' spermatophores over several hours before mating at the end of the day (i.e. before the transfer of a single sperm-containing 'macro' spermatophore). By experimental manipulation of male microspermatophore donation, I tested several hypotheses pertaining to the adaptive significance of nuptial gifts in this system. I found that microspermatophore transfer improves insemination, by causing the female reproductive tract to take in more sperm. This result reveals a previously undocumented function for premating nuptial gift donation among insects. Enhanced sperm transfer due to microspermatophore donation may represent male manipulation or an internal mechanism of post-copulatory choice by females. I also performed experimental manipulation of male photoperiod to investigate how time and gender influence nuptial gift production and mating behavior. I found that the timing of mating is limited in males but not females and that the time of pair formation has consequences for the degree of nuptial gift donation, which suggests that both mating timing and microspermatophore number is important for male reproductive success. Finally, I observed the mating behavior of several trigonidiine taxa for a comparative analysis of sexual behavior and found that other genera also utilize spermless microspermatophores, which suggests that microspermatophore donation may be a common nuptial gift strategy among swordtail crickets. The elaborate nuptial feeding behavior of Hawaiian swordtail crickets prior to mating represents a newly discovered strategy to increase male insemination success rather than mating success. Based on this unexpected result, it is worth exploring whether courtship behaviors in other cricket or insect mating systems have also evolved to increase sperm uptake.

Muscle Logic: New Knowledge Resource for Anatomy Enables Comprehensive Searches of the Literature on the Feeding Muscles of Mammals.

BACKGROUND: In recent years large bibliographic databases have made much of the published literature of biology available for searches. However, the capabilities of the search engines integrated into these databases for text-based bibliographic searches are limited. To enable searches that deliver the results expected by comparative anatomists, an underlying logical structure known as an ontology is required. DEVELOPMENT AND TESTING OF THE ONTOLOGY: Here we present the Mammalian Feeding Muscle Ontology (MFMO), a multi-species ontology focused on anatomical structures that participate in feeding and other oral/pharyngeal behaviors. A unique feature of the MFMO is that a simple, computable, definition of each muscle, which includes its attachments and innervation, is true across mammals. This construction mirrors the logical foundation of comparative anatomy and permits searches using language familiar to biologists. Further, it provides a template for muscles that will be useful in extending any anatomy ontology. The MFMO is developed to support the Feeding Experiments End-User Database Project (FEED, https://feedexp.org/), a publicly-available, online repository for physiological data collected from in vivo studies of feeding (e.g., mastication, biting, swallowing) in mammals. Currently the MFMO is integrated into FEED and also into two literature-specific implementations of Textpresso, a text-mining system that facilitates powerful searches of a corpus of scientific publications. We evaluate the MFMO by asking questions that test the ability of the ontology to return appropriate answers (competency questions). We compare the results of queries of the MFMO to results from similar searches in PubMed and Google Scholar. RESULTS AND SIGNIFICANCE: Our tests demonstrate that the MFMO is competent to answer queries formed in the common language of comparative anatomy, but PubMed and Google Scholar are not. Overall, our results show that by incorporating anatomical ontologies into searches, an expanded and anatomically comprehensive set of results can be obtained. The broader scientific and publishing communities should consider taking up the challenge of semantically enabled search capabilities.

Can the protein costs of bacterial resistance be offset by altered feeding behaviour?

1. Mounting an immune response is likely to be costly in terms of energy and nutrients, and so it is predicted that dietary intake should change in response to infection to offset these costs. The present study focuses on the interactions between a specialist grass-feeding caterpillar species, the African armyworm Spodoptera exempta, and an opportunist bacterium, Bacillus subtilis.
2. The main aims of the study were (i) to establish the macronutrient costs to the insect host of surviving a systemic bacterial infection, (ii) to determine the relative importance of dietary protein and carbohydrate to immune system functions, and (iii) to determine whether there is an adaptive change in the host's normal feeding behaviour in response to bacterial challenge, such that the nutritional costs of resisting infection are offset.
3. We show that the survival of bacterially infected larvae increased with increasing dietary protein-to-carbohydrate (P:C) ratio, suggesting a protein cost associated with bacterial resistance. As dietary protein levels increased, there was an increase in antibacterial activity, phenoloxidase (PO) activity and protein levels in the haemolymph, providing a potential source for this protein cost. However, there was also evidence for a physiological trade-off between antibacterial activity and phenoloxidase activity, as larvae whose antibacterial activity levels were elevated in response to immune activation had reduced PO activity.
4. When given a choice between two diets varying in their P:C ratios, larvae injected with a sub-lethal dose of bacteria increased their protein intake relative to control larvae whilst maintaining similar carbohydrate intake levels. These results are consistent with the notion that S. exempta larvae alter their feeding behaviour in response to bacterial infection in a manner that is likely to enhance the levels of protein available for producing the immune system components and other factors required to resist bacterial infections (‘self-medication’).

Deposit-feeding mechanisms and resource partitioning in tropical holothurians

Aspidochirote holothurians found on tropical reef flats feed on particulate deposits which form a variety of substrata. The synaptid holothurian Opheodesoma grisea (Semper) feeds in a similar manner by scraping deposits from the surfaces of sea grasses. Distributional and gut content analyses showed that species partitioning is on the basis of substratum and particle size preference. Scanning electron microscopy revealed that the tentacles of aspidochirotes have a nodular surface while those of O. grisea have a tessellated surface structure. The twelve different species examined were shown to have different tentacular surface textures which bore an apparent relationship with the mean particle sizes selected by the different species. Light microscope studies of tentacle sections confirmed earlier observations on the extent of the water vascular system in aspidochirote and pinnate tentacles. From these observations a functional interpretation is proposed for tentacular operation and the means of particle selection in such holothurians.

Relationships between lameness and feeding behaviour in cubicle-housed Holstein-Friesian dairy cows

The relationship between lameness and feeding behaviour in dairy cows is not yet fully understood. This study examined the effect of lameness on feeding behaviour at two points during lactation. Forty-five Holstein–Friesian dairy cows (average parity 3.3) were housed in cubicle accommodation after calving and fed a total mixed ration (TMR). At approximately 60 and 120 days post partum, 48 h of information on feeding behaviour (including number of meals eaten, meal duration, meal size and feeding rate) was collected for each animal using feed boxes fitted to a data recording system. At the same time points, locomotion scores were recorded for each cow as a measure of lameness (1.0-sound to 4.5-severely lame). Relationships between feeding behaviour and locomotion score were analysed using Residual Maximum Likelihood (REML) analysis. At both time points, cows with higher locomotion scores ate fewer (P < 0.001), larger meals (P < 0.001) and had a shorter total feeding time (P < 0.001). At day 60 post partum, an increase in locomotion score was associated with a decrease in dry matter intake (P < 0.05), but at day 120 post partum no relationship was found between locomotion score and DMI. No relationship was found at either time point between locomotion score and mean meal duration or rate of feeding. The results of this study suggest that the effect of lameness on feeding behaviour in dairy cows does not remain constant across lactation.

Trait-mediated indirect interactions in a marine intertidal system as quantified by functional responses

Studies of trait-mediated indirect interactions (TMIIs) typically focus on effects higher predators have on per capita consumption by intermediate consumers of a third, basal prey resource. TMIIs are usually evidenced by changes in feeding rates of intermediate consumers and/or differences in densities of this third species. However, understanding and predicting effects of TMIIs on population stability of such basal species requires examination of the type and magnitude of the functional responses exhibited towards them. Here, in a marine intertidal system consisting of a higher-order fish predator, the shanny Lipophrys pholis, an intermediate predator, the amphipod Echinogammarus marinus, and a basal prey resource, the isopod Jaera nordmanni, we detected TMIIs, demonstrating the importance of habitat complexity in such interactions, by deriving functional responses and exploring consequences for prey population stability. Echinogammarus marinus reacted to fish predator diet cues by reducing activity, a typical anti-predator response, but did not alter habitat use. Basal prey, Jaera nordmanni, did not respond to fish diet cues with respect to activity, distribution or aggregation behaviour. Echinogammarus marinus exhibited type II functional responses towards J. nordmanni in simple habitat, but type III functional responses in complex habitat. However, while predator cue decreased the magnitude of the type II functional response in simple habitat, it increased the magnitude of the type III functional response in complex habitat. These findings indicate that, in simple habitats, TMIIs may drive down consumption rates within type II responses, however, this interaction may remain de-stabilising for prey populations. Conversely, in complex habitats, TMIIs may strengthen regulatory influences of intermediate consumers on prey populations, whilst potentially maintaining prey population stability. We thus highlight that TMIIs can have unexpected and complex ramifications throughout communities, but can be unravelled by considering effects on intermediate predator functional response types and magnitudes.

Identifying optimal feeding habitat and proposed Marine Protected Areas (pMPAs) for the black-legged kittiwake (Rissa tridactyla) suggests a need for complementary management approaches

Marine Protected Areas (MPAs) are an important conservation tool. For marine predators, recent research has focused on the use of Species Distribution Models (SDMs) to identify proposed sites. We used a maximum entropy modelling approach based on static and dynamic oceanographic parameters to determine optimal feeding habitat for black-legged kittiwakes (Rissa tridactyla) at two colonies during two consecutive breeding seasons (2009 and 2010). A combination of Geographic Positioning System (GPS) loggers and Time-Depth Recorders (TDRs) attributed feeding activity to specific locations. Feeding areas were <30 km from the colony, <40 km from land, in productive waters, 25–175m deep. The predicted extent of optimal habitat declined at both colonies between 2009 and 2010 coincident with declines in reproductive success. Whilst the area of predicted optimal habitat changed, its location was spatially stable between years. There was a close match between observed feeding locations and habitat predicted as optimal at one colony (Lambay Island, Republic of Ireland), but a notable mismatch at the other (Rathlin Island, Northern Ireland). Designation of an MPA at Rathlin may, therefore, be less effective than a similar designation at Lambay perhaps due to the inherent variability in currents and sea state in the North Channel compared to the comparatively stable conditions in the central Irish Sea. Current strategies for designating MPAs do not accommodate likely future redistribution of resources due to climate change. We advocate the development of new approaches including dynamic MPAs that track changes in optimal habitat and non-colony specific ecosystem management.