300 research outputs found
Protein and energy nutrition of marine gadoids, Atlantic cod (Gadus morhua L.) and haddock (Melanogrammus aeglefinus L.)
No full text Primary goals of this thesis were to: 1) examine the in vivo digestion of macronutrients from conventional or alternative feed ingredients used in practical diets of juvenile gadoids (Atlantic cod and haddock), 2) document growth potential of fish at the juvenile grower phase given varying levels of dietary protein and energy and 3) assess the potential of in vitro pH-Stat methods for rapid screening protein quality of feed ingredients, specifically for gadoids. All primary research questions were linked to and built upon one another with the goal of gaining a better understanding of protein and energy utilization of juvenile grower phase gadoids. Studies showed that cod and haddock have a high capacity to utilize a wide range of dietary feed ingredients, such as fish meals, zooplankton meal, soybean products (meal, concentrate and isolate) and wheat gluten meal. New dietary formulations for gadoids may also utilize pulse meals, corn gluten meal, canola protein concentrate and crab meal. Digestibility data in this thesis is currently the only research that examined both in vivo and in vitro macronutrient digestibility of a large number and wide range of individual ingredients, specifically for gadoids. This is essential to gain new knowledge on protein and energy utilization as well as for least-cost ration formulations and effective substitution of ingredients into new formulations. Data has demonstrated a dietary digestible protein/digestible energy (DP/DE)ratio of 30 g DP/MJ DE is required for gadoids during the juvenile phase (in vitro closed-system pH-Stat assay for rapid screening protein quality of test ingredients that is ‘species-specific’ to gadoids. It is demonstrated that in vitro results generally reflected results obtained through conventional in vivo protein digestibility methods. Studies resulted in the first generation of a ‘gadoid-specific’ proteolytic enzyme extraction method and in vitro closed-system pH-Stat assay which may be useful to investigate protein digestion, absorption and metabolism of gadoids and further development of their feeds. </p
The mentoring cycle
No full textThe aim of this chapter is to explore the mentoring cycle and in particular, the concept of phases within the context of the mentoring relationship. The chapter begins by outlining a number of models that describe how mentoring relationships develop over time, such as Kram (1980, 1983), Missirian (1982), Clutterbuck (1985; 2004), and Westland (2015). The mentee and mentor perspective is explored by understanding the experiences of each, through insight, during various stages of the relationship. Next, the author identifies a number of empirical studies that have ‘tested’ the models to better understand their application to specific contexts (Westland, 2015). The models are compared and contrasted in order to identify the challenges associated with the concept of the mentoring cycle. The author also considers factors that influence the mentoring cycle and the effectiveness of the mentoring relationship. Finally, the author considers the implications of the mentoring cycle from a number of perspectives: mentoring relationships, program design, training for mentees and mentors, and future research agendas for both researchers and practitioners
Swamp Angel, Pottawatomie County
No full textBrandon Haddock, “Swamp Angel, Pottawatomie County,” Chapman Center Research Collections, https://ccrsresearchcollections.omeka.net/items/show/21.The author theorizes the name of "Swamp Angel" and its possible settlement by its remaining un-incorporated houses, grain silo and railroad tracks located on the floodplain of the Kansas River
Lipid metabolism of haddock (Melanogrammus aeglefinus)
No full textHaddock, a commercially important coldwater marine fish accumulates a high amount of dietary lipid in the liver (>60% lipid, wet weight). Several experiments were conducted to study the dietary lipid utilization by haddock, their lipid transport mechanisms and the biochemical basis of liver lipid deposition and catabolism. Juvenile haddock (6.9g) were fed three isonitrogenous diets containing 14, 16, 19 and 22% lipid to examine the effects of dietary lipid on growth, feed utilization, hepatosomatic index (HSI) and tissue lipid accumulation. Growth and feed efficiency of haddock was not significantly affected by increasing the lipid content of the diet. A significant increase in HSI (9.8–12.1%) and total liver lipid content (63.2–69.0%) was observed in haddock fed 14% versus 22% lipid, however, total muscle lipid content was unaffected. The liver fatty acid (FA) composition mirrored that of the diet. The muscle lipid (1%) contained a high proportion of polar lipid (84% lipid) and polyunsaturated FA (53% total FA). A dietary lipid level of 14% or less is recommended for use in juvenile haddock grower diets based on the results of this study. A series of liver function tests were also performed on the plasma of cultured haddock grouped on the basis of their HSI. No significant differences were observed between the 11.1, 13.0 and 17.3% HSI groups for any of the liver function parameters tested.Serum lipoproteins of post-absorptive juvenile haddock showed that HDL (high density lipoprotein) was the predominant lipoprotein class (1517 mg/dL) followed by LDL (low density lipoprotein; 467 mg/dL). A low level of VLDL (very low density lipoprotein; <50 mg/dL) was observed in serum. The concentration of total lipid in the serum averaged 1297 mg/dL. The phospholipid (PL), triacylglycerol (TG), cholesterol ester (CE) and cholesterol (CL) contents of serum were 57, 16, 16 and 11%, respectively. The fatty acid (FA) composition of HDL resembled that of the serum lipid and PL and it contained a higher percentage (51%) of polyunsaturated FA than VLDL (36%). High molecular weight apo B-like proteins were observed in the VLDL and LDL fractions. An apo A-I-like protein was predominant in the HDL fraction. The low level of VLDL (<50mg/dL) circulating in the serum suggests a low level of lipid (triacylglycerol) transport from the liver to the muscle in haddock. (Abstract shortened by UMI.).Source: Dissertation Abstracts International, Volume: 64-07, Section: B, page: 3001.Advisers: Santosh P. Lall; Mary A. McNiven
Effect of dietary lipid level on fatty acid beta-oxidation and lipid composition in various tissues of haddock, Melanogrammus aeglefinus L
No full textHaddock (Melanogrammus aeglefinus) is a gadoid fish species that deposits dietary lipid mainly in the liver. The fatty acid (FA) beta-oxidation activity of various tissues was evaluated in juvenile haddock fed graded levels of lipid. The catabolism of a radiolabelled FA, [1-(14)C]palmitoyl-CoA, through peroxisomal and mitochondrial beta-oxidation was determined in the liver, red and white muscle of juvenile haddock fed 12, 18 and 24% lipid in the diet. There was no significant increase in the mitochondrial or peroxisomal beta-oxidation activity in the tissues tested as the dietary lipid level increased from 12 to 24%. Peroxisomes accounted for 100% of the beta-oxidation observed in the liver, whereas mitochondrial beta-oxidation dominated in the red (91%) and white muscle (97%) of juvenile haddock. Of the tissues tested, red muscle possessed the highest specific activity for beta-oxidation expressed on a per mg protein or per g wet weight basis. However, white muscle, which forms over 50% of the body mass in gadoid fish was the most important tissue in juvenile haddock for overall FA catabolism. The total lipid and FA composition of these tissues were also determined. This study confirmed that the liver was the major lipid storage organ in haddock. The hepatosomatic index (HSI; 10.0-15.2%) and lipid (73.8-79.3% wet wt.) in the liver increased significantly as dietary lipid was increased from 12 to 24% lipid. There was no significant increase in the lipid composition of the white muscle (0.8% wet wt.), red muscle (1.9% wet wt.) or heart (2.5% wet wt.).LR: 20061115; PUBM: Print; JID: 9516061; 0 (Carbon Radioisotopes); 0 (Dietary Fats); 0 (Fatty Acids); 0 (Lipids); 0 (Lipoproteins, VLDL); 1763-10-6 (Palmitoyl Coenzyme A); ppublishSource type: Electronic(1
Archeterokrohnia docrickettsae Thuesen & Haddock, 2013, n. sp.
No full textArcheterokrohnia docrickettsae n. sp. (Figs 1–4) Etymology. Named for the Monterey Bay Aquarium Research Institute’s ROV Doc Ricketts, in turn named in honor of marine biologist Ed Ricketts, co-author of Sea of Cortez (Steinbeck & Ricketts 1941) and inspiration for the character “Doc” in the novel Cannery Row (Steinbeck 1945). Material examined. Holotype: The single specimen of this species is deposited in the Santa Barbara Museum of Natural History (SBMNH)—a mature individual, 28.5 mm total length captured at 3245 m depth, at the north end of Pescadero Basin in the Gulf of California, Mexico (24 ° 22 ’ 2.47 ” N, 109 ° 12 ’ 29.44 ” W), 24 February 2012 (SBMNH No. 235523). Description. Total body length excluding tail fin (TL) 28.5 mm. Tail section 55.2 % of TL. Head blunt when hooded, triangular after preservation, head width 3.5 mm. Hooks 15 / 15, slender brown, dorsalmost three hooks on each side smaller. Anterior teeth 11 / 10, with wide bases of uneven sizes. Posterior teeth 4 / 4, small, about 25 % length of anterior teeth, clustered together in front of a plate at posteriormost part of vestibular organ. Vestibular organ located laterally on both sides of anterior teeth, joining together in an extension below posterior teeth and ending in a plate with small denticles. No vestibular papillae observed. Apical organ triangular, protruding from hood while alive. Eyes absent. Corona ciliata horseshoe-shaped. Trunk section of fairly uniform width (4.0 mm); body begins to taper posteriorly at tail/trunk junction. Body with slight ventral bend at tail/trunk junction; trunk section bright orange throughout in life. Anterior part of gut forms red esophagus once preserved; gut ivorycoloured and opaque. Transverse musculature 80 % of trunk, 17 % of tail. Ventral ganglion beginning at midpoint of trunk section, embedded within alveolar tissue on posterior half of trunk section, robust and elongated. One pair of lateral fins, rayed, starting just anterior of tail/trunk junction extending to the seminal vesicles. Small extension of each lateral fin ending in a ciliary fence, slightly posterior of anus. Ovaries cob-like, with many ova of different sizes. Annex gland present; annex gland diverticulum not observed. The specimen had mated, and each seminal receptacle contained a sperm packet. Seminal vesicles with inner core clearly differentiated from outer section; both parts ‘hooked’ anteriorly. Tail fin reaching posterior part of seminal vesicles, its form spathulate with 6 prominent ciliary fence organs on both ventral and dorsal sides. Further diagnostic information is given in Table 1. Remarks. This species is placed in the genus Archeterokrohnia on the basis of its extensive transverse musculature (~ 80 % or more of the trunk section), a tail section that is 50 % or more of the total body length, transverse musculature present in the tail section, a single lateral fin, and apical head organs. At 28.5 mm in length, A. docrickettsae is the largest species in the genus. Comparisons with the other three species of Archeterokrohnia are given in Table 1 based on the information summarized in Kapp (1991), following her format. A short artificial key is presented below to readily distinguish the four species of Archeterokrohnia. ......continued on the next pagePublished as part of Thuesen, Erik V. & Haddock, Steven H. D., 2013, Archeterokrohnia docrickettsae (Chaetognatha: Phragmophora: Heterokrohniidae), a new species of deep-sea arrow worm from the Gulf of California, pp. 320-328 in Zootaxa 3717 (3) on pages 321-322, DOI: 10.11646/zootaxa.3717.3.2, http://zenodo.org/record/22200
Interannual differences in larval haddock survival : hypothesis testing with a 3D biophysical model of Georges Bank
No full textAuthor Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Fisheries Oceanography 23 (2014): 521–553, doi:10.1111/fog.12087.The ultimate goal of early life studies of fish over the past century has been to better understand recruitment variability. As evident in the Georges Bank haddock (Melanogrammus aeglefinus) population, there is a strong relationship between recruitment success and processes occurring during the planktonic larval stage. This research sought new insights into the mechanisms controlling the recruitment process in fish populations by using biological-physical modeling methods together with laboratory and field data sets. We created the first three-dimensional model of larval haddock on Georges Bank by coupling models of hydrodynamics, lower trophic levels, a single copepod species, and larval haddock. Interactions between feeding, metabolism, growth, vertical behavior, advection, predation, and the physical environment of larval haddock were quantitatively investigated using the coupled models. Particularly, the model was used to compare survival over the larval period and the sources of mortality in 1995 and 1998, two years of disparate haddock recruitment. The results of model simulations suggest that the increased egg hatching rates and higher food availability, which reduced starvation and predation, in 1998 contributed to its larger year-class. Additionally, the inclusion of temperature-dependent predation rates produced model results that better agreed with observations of the mean hatch date of survivors. The results from this biophysical model imply that food-limitation and its related losses to starvation and predation, especially from hatch to 7 mm, may be responsible for interannual variability in recruitment and larval survival outside of the years studied.Financial support was provided by a WHOI Watson Fellowship, a WHOI Coastal Ocean
Institute Student Research Proposal Award, and GLOBEC grants NA17RJ1223 (NOAA)
and OCE0815838 (NSF).2015-11-1
A test of the provisioning hypothesis of recruitment control in Georges Bank haddock
No full textThe haddock (Melanogrammus aeglefinus) stock of the Georges Bank region of the US Northeast Continental Shelf displays a pattern of large, episodic recruitments. Among the hypothesized controlling mechanisms is the idea that recruitment events are related to provisioning of pre-spawning haddock by the fall bloom the year before. With the occurrence of a recent large recruitment event in 2013, it would be prudent to retest this hypothesis. Fall bloom magnitude was positively correlated (r=0.645, p=0.005) with haddock survivor ratio (recruits per spawning biomass) including data from the 2013 recruitment. This relationship identifies a pathway of bottom up control of a resource species, thus focusing concern over recent changes in lower trophic level productivity.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
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