Post-prandial response in hepatopancreas and haemolymph of Penaeus monodon fed different diets. Omics insights into glycoconjugate metabolism, energy utilisation, chitin biosynthesis, immune function, and autophagy

Raw materials or bioactive ingredients trigger mechanisms to assimilate nutrients and activate metabolic pathways that promote growth, immune function, or energy storage. Our understanding of these processes at a molecular level remains limited in aquaculture, especially in shrimp. Here, hepatopancreas proteomics and haemolymph metabolomics were used to investigate the post-prandial response of black tiger shrimps (Penaeus monodon) fed a conventional fishmeal diet (FM); a diet supplemented with the microbial biomass Novacq™ (NV); krill meal (KM); or, fasted (FS). Using FM as a control, a 2-fold change in abundance threshold was implemented to determine the significance of proteins and metabolites. NV fed shrimp showed preference for energy derived from carbohydrates indicated by a strong signature of glycoconjugate metabolism and activation of the amino- and nucleotide sugar metabolic pathway. KM activated the glyoxylate and dicarboxylate pathway that denoted shrimp preference for lipidic energy. KM also influenced energy generation by the TCA cycle inferred from higher abundance of the metabolites succinic semialdehyde, citric acid, isocitrate, alpha ketoglutarate and ATP and downregulation of the enzyme isocitrate dehydrogenase that catalyses oxidative decarboxylation of isocitrate. FS shrimp displayed down-regulation of oxidative phosphorylation and resorted to internal lipid reserves for energy homeostasis displaying a strong signature of autophagy. Pyrimidine metabolism was the preferred energy strategy in this group. Our study also provided evidence that during fasting or consumption of specific ingredients, shrimp share common pathways to meet their energy requirements, however, the intensity at which these pathways were impacted was diet dependent.

Intensification of Penaeid Shrimp Culture: An Applied Review of Advances in Production Systems, Nutrition and Breeding

Intensification of the shrimp sector, also referred to as vertical expansion, has been predominately driven by consecutive incidences of global disease outbreaks, which have caused enormous economic loss for the main producer countries. A growing segment of the shrimp farming industry has opted to use production systems with higher density, biosecurity, and operating control to mitigate the risks posed by disease. However, successful super-intensive shrimp production is reliant on an advanced understanding of many important biological and economic parameters in the farming system, coupled with effective monitoring, to maintain optimal production. Compared to traditional extensive or semi-intensive systems, super-intensive systems require higher inputs of feed, energy, labor, and supplements. These systems are highly sensitive to the interactions between these different inputs and require that the biological and economical parameters of farming are carefully balanced to ensure success. Advancing nutritional knowledge and tools to support consistent and efficient production of shrimp in these high-cost super-intensive systems is also necessary. Breeding programs developing breeding-lines selected for these challenging super-intensive environments are critical. Understanding synergies between the key areas of production systems, nutrition, and breeding are crucial for super-intensive farming as all three areas coalesce to influence the health of shrimp and commercial farming success. This article reviews current strategies and innovations being used for Litopenaeus vannamei in production systems, nutrition, and breeding, and discusses the synergies across these areas that can support the production of healthy and high-quality shrimp in super-intensive systems. Finally, we briefly discuss some key issues of social license pertinent to the super-intensive shrimp farming industry.

Feeding Behaviour and Bioavailability of Essential Amino Acids in Shrimp Penaeus monodon Fed Fresh and Leached Fishmeal and Fishmeal-Free Diets

Simple Summary

While success has been achieved with replacing fishmeal entirely in diets for whiteleg shrimp Litopenaeus vannamei, giant tiger prawn Penaeus monodon still requires fishmeal for optimum culture performance. Crystalline amino acid (CAA) supplementation is becoming popular in shrimp feed formulation and is needed in low fishmeal diets as common alternative protein sources are typically deficient in essential amino acids, such as methionine and lysine. Furthermore, the slow feeding behaviour of shrimp compared to other cultured aquatic species means that feeds can lose specific nutrients before they are consumed. In particular, highly soluble CAA are prone to leaching. In this study, we examined the feeding behaviour, CAA leaching loss and AA uptake in large Penaeus monodon juveniles through a series of short-term experiments using a terrestrial meal-based formulation (TM) enriched with CAA and a traditional fishmeal-based formulation (FM). Feeding behaviour and nutrient bioavailability was found to be similar for the two diets. However, leaching over as little as 60 min had a major impact on AA absorption for the TM diet. The growth implications associated with leaching losses need to be investigated. However, the results indicate the need for careful feeding management as increased reliance on CAA for P. monodon culture could lead to suboptimal nutrition.

Abstract

The complete replacement of fishmeal with terrestrial meals did not have a negative impact on the attractiveness, palatability, and apparent digestibility of the formulation. Shrimp were found on average to eat more and have similar appetite revival on the terrestrial meal-based formulation (TM) diet compared to the traditional fishmeal-based formulation (FM) diet. However, methionine (Met) and lysine (Lys) leached out rapidly from the TM diet, and as a result, this initially overfortified diet showed lower levels of those AA in comparison to FM after 60 min immersion. Both dietary Lys and Met were sub-optimal in TM within 120 min of immersion, whereas in comparison, the FM diet supplied consistent levels of EAA for up to 240 min immersion. Nonetheless, shrimp fed fresh TM had significantly higher peak haemolymph concentrations at 30 and 60 min for total AA, Met, and Lys than FM-fed shrimp. The over-supply of CAA far compensated leaching losses, and CAA were well absorbed and used by the shrimp within 120 min, with no obvious signs of asynchronous absorption of CAA to protein-bound AA. However, shrimp fed the TM diet that had leached out for 60 min, had haemolymph concentrations of Met and Lys that were only 41% and 44% of the ones on fresh feed respectively, while there was a negligible effect of leaching on FM. This study provides further insight into the feeding behaviour and bioavailability of dietary amino acids for P. monodon juveniles.

The impact of seismic air gun exposure on the haemolymph physiology and nutritional condition of spiny lobster, Jasus edwardsii

There is a critical knowledge gap regarding the impacts of seismic air gun signals on the physiology of adult crustaceans. We conducted four controlled field experiments to examine the impact of seismic acoustic signals on spiny lobster, Jasus edwardsii. Seismic air gun exposure suppressed total haemocyte count (THC) for up to 120days post-exposure, suggesting a chronic negative impact of immune competency. THC levels after 365days post-exposure, were elevated two fold, potentially indicating an immune response to infection. Haemolymph refractive index was reduced after 120days post exposure in one experiment, suggesting a chronic impairment of nutritional condition. There was no effect of air gun exposure on 24 haemolymph biochemical parameters, hepatopancreas index or survival. Collectively these results indicate that the biochemical haematological homeostasis of J. edwardsii is reasonably resilient to seismic acoustic signals, however, air gun exposure may negatively influence the lobster's nutritional condition and immunological capacity.

Near-Infrared Spectroscopy as a Novel Non-Invasive Tool to Assess Spiny Lobster Nutritional Condition

Rapid non-invasive monitoring of spiny lobster nutritional condition has considerable application in the established fishery, live market and prospective aquaculture. The aim of this research was to test the feasibility of near-infrared spectroscopy (NIRS) as a novel non-invasive tool to assess the nutritional condition of three lobster species. Lobster (n = 92) abdominal muscle dry matter (AM_DM) and carbon content (AM_C) correlated significantly with indices of nutritional condition including hepatopancreas dry matter (HP_DM; r_ho = 0.83, 0.78), total lipid content (HP_TL; r_ho = 0.85, 0.87) and haemolymph total protein (TP; r_ho = 0.89, 0.87 respectively). Abdominal muscle nitrogen content (AM_N) was a poor correlate of nutritional condition. Models based on FT-NIR scanning of whole lobster tails successfully predicted AM_DM, AM_N and AM_C (RMSECV = 1.41%, 0.35% and 0.91%; R² = 0.75, 0.65, 0.77, respectively), and to a lower accuracy HP_DM, HP_TL and TP (RMSECV = 6.22%, 8.37%, 18.4 g l^-1; R² = 0.51, 0.70, 0.83, respectively). NIRS was applied successfully to assess the condition of spiny lobsters non-invasively. This pilot study paves the way for the development of crustacean condition models using portable non-invasive devices in the laboratory or in the field.

Efficacy of glycine powder air polishing in comparison with sodium bicarbonate air polishing and ultrasonic scaling - a double-blind clinico-histopathologic study

BACKGROUND

Subgingival biofilm removal using glycine powder air polishing (GPAP) has antecedently been shown to be safe. The hypothesis that GPAP is efficacious during periodontal maintenance therapy and results in less gingival erosion than sodium bicarbonate air polishing (SBAP) or ultrasonic scaling was assessed.

METHODS

Initial periodontal therapy was performed in each of the 22 chronic periodontitis patients having residual 5 mm probing depth in each quadrant and were randomly assigned to one of the following interventions: GPAP (test), SBAP (positive control), ultrasonic scaling (positive control) or no treatment. Clinical parameters were assessed, and gingival biopsies were taken immediately after instrumentation and sent for histological quantification.

RESULTS

Significant improvement in plaque and gingival index scores were noted in glycine powder air-polishing and ultrasonic group. GPAP resulted in minor erosion of the gingival epithelium (score 1 & 2), whereas positive control specimens displayed moderate to severe erosions (score 3 & 4). Difference between GPAP and positive control was significant. (P < 0.05).

CONCLUSION

GPAP results in clinically significant improvement in plaque and gingival index scores and histologically causes less gingival erosion than SBAP or ultrasonic instrumentation, further supporting the safety of this debridement technique in periodontal maintenance therapy.

Comparison of visual inspection and Papanicolau (PAP) smears for cervical cancer screening in Honduras: should PAP smears be abandoned?

OBJECTIVE

To compare visual inspection with acetic acid (VIA) to Papanicolau (PAP) smears in a community setting in a developing nation.

METHODS

Women undergoing cervical cancer screening in Honduras received either VIA and PAP smears (VIA/PAP group) or PAP smears alone (PAP-only group). Local healthcare providers performed PAP screening. A VIA-trained nurse performed VIA exams. All PAP smears were processed in Honduras. PAP smears from the VIA/PAP group were reviewed in the United States. Women with positive VIA or PAP tests were offered colposcopy. We compared the relative accuracy of PAP smears and VIA and the proportions of women completing follow-up colposcopy after positive screening tests.

RESULTS

In total, 1709 PAP smears were performed including women from both the VIA/PAP and PAP-only groups. Nine PAP smears were positive (0.5%). Three women completed colposcopy (33%). All three had biopsy-confirmed dysplasia. In the VIA/PAP group (n = 339), 49 VIA exams were abnormal (14%) and two PAP smears were abnormal when read in Honduras (0.6%). When reviewed in the United States, 14 of the 339 PAP smears were abnormal (4%). Forty women (83%) completed follow-up colposcopy after a positive VIA exam. Twenty-three had biopsy-proven dysplasia. All 23 dysplasia cases had negative PAP smear readings in Honduras; four PAP smears were reclassified as positive in the United States.

CONCLUSIONS

Although few developing countries can maintain high-quality PAP smear programmes, many governments and charitable organizations support cervical cancer screening programmes that rely on PAP smears. This study underscores the need to promote alternative technologies for cervical cancer screening in low-resource settings.

Simple sequence repeat analysis of a clonally propagated species: a tool for managing a grape germplasm collection

The USDA germplasm repositories help to preserve the genetic variability of important crop species by collecting and maintaining representative cultivars and related germplasm. Simple sequence repeat markers with high allelic diversity were used to type 41 grapevines from 40 accessions. All vines were either seedless table grape cultivars or cultivars with names similar to table grape cultivars. The proportion of shared alleles was selected as the most appropriate statistical measure of genetic distance for this population. In conjunction with morphological traits, known synonyms were confirmed and a previously unknown synonym was discovered. An alleged synonym in the literature was disproved by the DNA data. The data were consistent with known parentage, where such data were available. Two mislabeled vines in the USDA collection were identified. UPGMA grouped the cultivars loosely into three groups: a group of nine mostly Middle Eastern cultivars, a group of 22 accessions mostly from Russia and Afghanistan that were morphologically similar to 'Thompson Seedless', and a third very loose group of 11 accessions consisting mostly of eastern European wine grape cultivars. The limitations and usefulness of this type of analysis are discussed.

Patients and profits: the relationship between HMO financial performance and quality of care

This paper matches health plans' financial performance with information on quality ratings as measured by 1997 Health Plan Employer Data and Information Set (HEDIS) 3.0 data. We address three policy questions: (1) Is the quality of care delivered by a plan influenced by the plan's financial performance? (2) Do for-profit plans behave differently than nonprofits do? (3) What other factors are associated with variation in plan performance? We find, first, that more profitable plans achieve higher quality scores in subsequent years. Profits may enable a plan to pursue higher quality of care and invest in better management systems. Second, there is little systematic evidence that for-profit plans have different HEDIS scores than not-for-profits have.

Determinants of managed care penetration

This paper examines factors associated with differences in managed care penetration across geographic areas. Two alternative measures of managed care penetration are considered: the percentage of revenue physicians received from managed care contracts and market survey data on enrollments in managed care plans. Results are similar for both types of measures. Our analysis suggests that demographics, labor market characteristics and supply side variables including the level of concentration in hospital markets, hospital occupancy rates and the practice organization patterns of physicians are all important determinants of managed care penetration.

The effect of managed care on the incomes of primary care and specialty physicians

OBJECTIVE

To determine the effects of managed care growth on the incomes of primary care and specialist physicians.

DATA SOURCES

Data on physician income and managed care penetration from the American Medical Association, Socioeconomic Monitoring System (SMS) Surveys for 1985 and 1993. We use secondary data from the Area Resource File and U.S. Census publications to construct geographical socioeconomic control variables, and we examine data from the National Residency Matching Program.

STUDY DESIGN

Two-stage least squares regressions are estimated to determine the effect of local managed care penetration on specialty-specific physician incomes, while controlling for factors associated with local variation in supply and demand and accounting for the potential endogeneity of managed care penetration.

DATA COLLECTION

The SMS survey is an annual telephone survey conducted by the American Medical Association of approximately one percent of nonfederal, post-residency U.S. physicians. Response rates average 60-70 percent, and analysis is weighted to account for nonresponse bias.

PRINCIPAL FINDINGS

The incomes of primary care physicians rose most rapidly in states with higher managed care growth, while the income growth of hospital-based specialists was negatively associated with managed care growth. Incomes of medical subspecialists were not significantly affected by managed care growth over this period. These findings are consistent with trends in postgraduate training choices of new physicians.

CONCLUSIONS

Evidence is consistent with a relative increase in the demand for primary care physicians and a decline in the demand for some specialists under managed care. Market adjustments have important implications for health policy and physician workforce planning.

The provision of primary care: does managed care make a difference?

Drawing on a nationally representative survey of physicians, this paper examines the extent to which physicians split their time between primary care and non-primary care activities and whether managed care makes a difference. We find that managed care does matter: Physicians have been narrowing their scope of practice, and the trend is linked to their involvement with managed care plans. These findings have implications for workforce policy and training, regulation of managed care contracting, and the quality of care.

The impact of managed care on the physician marketplace

OBJECTIVE

To examine the impact of managed care on the employment and compensation of primary care and specialty physicians, as measured by changes in income, physician-to-population ratios, and specialty choices.

METHODS

The authors used data from the American Medical Association's Socioeconomic Monitoring System survey, a nationally representative 1% random survey of post-residency patient-care physicians, and location data from the AMA Masterfile to evaluate the relationship between the growth in managed care from 1985 to 1993 and (a) inflation-adjusted physician incomes and (b) physician-to-population ratios for primary care physicians and specialists. They also used data from the National Residency Matching Program for 1989 through 1995 to look at trends in available positions and specialty choices.

RESULTS

Primary care incomes grew 4.78% annually ($33,526 cumulatively) in states with the highest managed care growth, compared to 1.20% ($7448 cumulatively) in the lowest quartile of managed care growth. The difference in income growth for medical and surgical subspecialists between the highest and lowest quartiles was not statistically significant. The incomes of radiologists, anesthesiologists, and pathologists (RAPs) rose 0.14%, or $1700, in the highest quartile versus 4.14% ($58,558) in the lowest. Subspecialists per capita did not differ by quartile of managed care growth; but RAPs per capita increased fastest in states in the lowest quartile. Between 1989 and 1995, the number of family practice and pediatric residency positions that were filled rose 32%, while the number filled remained stable for medical and surgical subspecialists and the number of RAP positions filled fell 14%.

CONCLUSIONS

The growth in managed care has been associated with significant changes in physician incomes and practice locations. Between 1985 and 1993, states with the fastest growth in managed care penetration saw the highest rate of growth in primary care physicians' income and the slowest rate of growth in RAP physicians' income. At the same time, the number of RAP physicians grew most rapidly in those states with the lowest rate of managed care growth. Finally, between 1989 and 1995, there was a dramatic increase in the number of primary care residency positions filled and a marked decrease in the number of RAP residency positions filled across the country.