Liver Meal Research Articles

Apparent digestibility coefficients of animal feed ingredients for olive flounder (Paralichthys olivaceus)

Apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, nitrogen-free extract, energy and essential amino acids in animal-based feed ingredients were determined for olive flounder (Paralichthys olivaceus). A reference diet (RF) was formulated to contain 1.0% chromic oxide (Cr2O3) as an inert indicator. Nine test diets were formulated to contain RF and one of the feed ingredients (pollock meal [PM], jack mackerel meal [JMM], anchovy meal [AM], cod meal [CM], sardine meal [SM], sand eel meal [SEM], tuna meal [TM], meat meal [MM] and squid liver meal [SLM]) at a 7:3 ratio in each diet designated as PM, JMM, AM, CM, SM, SEM, TM, MM and SLM, respectively. Olive flounder, averaging 150 ± 8.0 g, were stocked at a density of 25 fish per tank in 400-L fiberglass tanks attached with fecal collection columns. Feces were collected from triplicate groups of fish one time a day for four weeks. Dry matter and crude protein ADCs of CM and SEM were significantly higher than the other tested ingredients. Lipid ADCs of JMM, CM and SEM were significantly higher than the other test ingredients. Energy ADCs of CM and SEM were significantly higher than that of the other tested ingredients. The availability of amino acids in CM was generally higher than the other animal protein sources. PM exhibited the lowest amino acid availability among the treatments. Interestingly, MM exhibited significantly higher nutrient digestibility than several marine-based ingredients. However, CM and SEM are seeming to be highly digestible and effective to use in olive flounder diet compared to the other tested ingredients. Overall, the results of this study provide information about the bioavailability of nutrients and energy in animal feedstuffs to apply when formulating cost-effective practical feeds for olive flounder.

Animal by‐products with or without enzymatic hydrolysis completely replacement of fish meal in genetically improved farmed tilapia diets ( Oreochromis niloticus )

An 8-week feeding trial was performed to examine the potential of total replacement of fish meal with animal by-products with or without enzymatic components in juvenile genetically improved farmed tilapia (GIFT) diets, Oreochromis niloticus, (mean initial weight, 19.71 ± 0.28 g), reared in RAS system. Five isonitrogenous and isoenergetic diets were formulated with fish meal for the diets with total replacement of the isonitrogenous amounts of enzymatic fish meal (E-FM), chicken liver meal (CLM), enzymatic chicken liver meal (E-CLM), dried porcine solubles (DPS) and enzymatic dried porcine solubles (E-DPS) respectively. The results indicated that the weight gain rate (WGR) and specific growth rate (SGR) in the FM group were significantly higher than the E-FM and E-CLM groups (p < .05), but the specific growth rate (SGR) in the E-CLM group lower than the E-FM group. The feed conversion ratio (FCR) in FM and CLM was significantly lower than the E-FM, E-CLM and E-DPS groups (p < .05), and no significant difference was observed among the FM, CLM and DPS groups (p > .05). The values of the protein retention efficiency (PRE) and protein efficiency ratio (PER) in FM, CLM and DPS groups were significantly higher than the E-CLM group (p < .05). The values of feed intake ratio (FIR) in FM and CLM groups were significantly lower than the E-FM, E-CLM and E-DPS groups (p < .05). There was no significant difference in the whole body contents of moisture, crude lipid and crude ash among the FM and E-CLM groups (p > .05). The whole body contents of crude protein in the FM group were significantly higher than the E-FM, CLM, E-CLM DPS and E-DPS groups (p < .05). The apparent digestibility coefficients (ADC) of dry matter, crude protein and crude lipid in the FM, E-FM, E-CLM and E-DPS groups were not significantly different (p > .05). The serum glucose(GLU), total cholesterol (TCHO) and triglycerides (TG), or the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were not affected by the different treatments (p > .05). There was no significant difference in serum total protein (TP) or albumin (ALB) and between the FM group and other groups (p > .05). There was no significant difference in the serum urea nitrogen (BUN) content in the FM, CLM, E-CLM and DPS groups (p > .05). Fish fed with the CLM and DPS diets had significantly lower hepatic GHR1, IGF1 and IGF2 gene mRNA expression levels than in fish fed the FM diet (p < .05). The present data showed that 6% of dietary fish meal can be totally replaced by the chicken liver meal and dried porcine solubles with no effect on the growth performance of GIFT strain tilapia.

Feed preference and growth response of juvenile Litopenaeus vannamei to supplementation of marine chemoattractants in a fishmeal‐challenged diet

AbstractThis study compared the feed preference and growth response of Litopenaeus vannamei to chemoattractants. A diet with 3% fishmeal was supplemented with either 3% salmon meal (POS), 3% soy protein concentrate (NEG), 3% krill meal (KRM), 3% squid meal (SQM), 3% shrimp head meal (SHM), 3% shrimp meal (SM), 3% squid liver meal (SLM), or 5% liquid sardine hydrolysate (SAH). Shrimp with a body weight (BW) of 0.99 ± 0.08 g were stocked at 100 animals/m2 in 56 tanks of 1 m3 and fed 10 times daily for 74 days. Feed preference was evaluated by feeding shrimp of 10.87 ± 1.82 g in excess twice a day for 10 days in two separate feeding trays allocated in 50 tanks of 0.5 m3. Survival reached 93.3 ± 5.80% and was unaffected by supplementation. Final BW was the highest for shrimp fed the KRM‐supplemented diet (11.97 ± 0.93 g), followed by POS (11.11 ± 0.77 g) and SQM (11.01 ± 1.17 g). Diets SHM, SM, SLM, and NEG showed a lower shrimp BW than POS, but were not statistically different among them. Shrimp fed the SAH diet achieved the lowest BW (10.06 ± 1.02 g). The highest gained yield was obtained with diets KRM and POS. No statistical difference was observed in shrimp yield among other diets. The lowest feed conversion ratio (FCR) was achieved with shrimp fed KRM (1.31 ± 0.05) when compared to diets SHM (1.47 ± 0.05), SAH (1.47 ± 0.07), and SLM (1.45 ± 0.17). Two‐by‐two comparisons indicated that shrimp preferred SHM and KRM, except when these were compared to SQM and SLM. No difference in feed preference was found between diets with SQM and SLM. SAH was the least preferred raw material in all comparisons. Results indicated that KRM acts as a powerful feeding effector and growth enhancer in fishmeal‐challenged diets for whiteleg shrimp. A dietary supplementation with 3% KRM is more effective than the same dose of any other chemoattractant evaluated.

INFLUENCE OF SQUID LIVER MEAL IN MATURATION DIET ON GONADOSOMATIC INDEX AND GONADAL AMINO ACID CONTENT OF GOLDEN SPOTTED RABBITFISH, Siganus guttatus

A four months feeding trial was conducted to evaluate the effects of two maturation diets containing either fishmeal (FM) or squid liver meal (SLM) as the major protein source on growth, gonadosomatic index and gonadal bio-chemical profiles of golden spotted rabbitfish, Siganus guttatus. The two tested diets were formulated to be iso-nitrogenous (40%) and iso-lipidic (14%) and supplemented with several micronutrients specifically for gonadal development. The initial weight of golden spotted rabbitfish used were 352.6 ± 45.0 g and stocked into four of 2 m x 2 m x 2.5 m net cages with 25 fish per cage. The test diets were fed to the stocks twice a day. After four months feeding, the weight gains (WG) of broodstock fed the two diets were nearly similar in which FM had WG of 40.1 ± 2.2% and 42.8 ± 2.0% for SLM. The GSI of male fed SLM diet was similar to that of fed with FM. However, the GSI of female fed FM was 5.6 ± 0.1% significantly lower (P&lt;0.05) than SLM which was 11.4 ± 0.5%. Furthermore, total amino acid (TAA) in spermatocyte was significantly (P&lt;0.05) influenced by dietary SLM indicated by its higher TAA (62.4%) compared to TAA content of FM group (46.1%). Similarly, the TAA content in oocyte was significantly (P&lt;0.05) improved when fed SLM. The dietary SLM did not affect the TAA content in the fillet of rabbitfish demonstrated by the similarity of the fillet TAA content in the two groups which was 55.6% for FM and 54.1% for SLM. Dietary SLM enhanced GSI of female broodstocks and profile of amino acid in the gonad of golden spotted rabbitfish, Siganus guttatus.

PHARMACOLOGICAL REGULATION OF DIGESTION IN THE ANAUTOGENOUS FLESH FLY, Sarcophaga crassipalpis, BY SIMPLE INJECTION OF 6-HYDROXYDOPAMINE.

Female anautogenous Sarcophaga flesh flies need a protein meal to start large-scale yolk polypeptides (YPs) production and oocyte maturation. Protein meal rapidly elicits a brain-dependent increase in midgut proteolytic activity. Trypsin and chymotrypsin together represent over 80% of protease activity in liver-fed flies. Abdominal injection of 6-hydroxydopamine (6-OHDA) dose-dependently prohibits this increase in proteolytic activity at translational level in a similar way as post liver feeding decapitation. Delayed injection of 6-OHDA later than 6 h post liver meal has no effect. In flesh flies, chemical decapitation by 6-OHDA, by interrupting the brain-gut dopaminergic signaling, can be used as tool for the controlled inhibition of midgut proteolytic activity and subsequent ovarial development. Inhibition of ovarial development is probably indirect due to a deficit in circulating amino acids needed for YPs synthesis.

Effect of Different Animal Protein Sources on Growth and Nutrient Utilization of Guppy, Poecilia reticulata Fingerlings

Based on the nutrient requirement of guppy, Poecilia reticulata fingerlings as reported earlier, nine experimental diets with 300 g protein, 100 g lipid and 16.72 MJ digestible energy/kg diet were formulated using snail meat (D-1), freshwater fish processing waste (D-2), surimi by-product (D-3), chicken offal (D-4), earthworm (D-5), squid (D-6), mussel (T-7), chicken liver (T-8) and lean prawn (T-9) as major protein source in addition to fish meal and peanut oil cake and fed ad libitum to the fish (0.27 ± 0.01 g) for a period of 60 days. Twenty-seven indoor circular fiber-reinforced plastic tanks (10 fish/tank) with 40 L of water were used for rearing the fish. At the end of the experiment, it was found that the guppy fed surumi by-product, squid, mussel and lean prawn meal diets had significantly higher (p < 0.05) weight gain, specific growth rate and protein efficiency ratio and lowest (p < 0.05) food conversion ratio than the snail, freshwater fish processing waste, chicken offal, earthworm and chicken liver meal diets and therefore, these four could be used as dietary protein source in formulating the diets for guppy. However, to formulate the cost-effective diets for guppy fingerlings, the use surimi by-product is suggested as it is being discarded as waste material and therefore, available free of cost.

Attractability and palatability of protein ingredients of aquatic and terrestrial animal origin, and their practical value for blue shrimp, Litopenaeus stylirostris fed diets formulated with high levels of poultry byproduct meal

Properties of two kinds of poultry byproduct meal (PBM), blood meal (BLM), hydrolyzed feather meal (HFM), anchovy fishmeal (AFM), fish hydrolysate (FHD), squid liver meal (SLM) and krill meal (KRL) as feeding effectors (attractants and palatability factors) were studied in juvenile blue shrimp Litopenaeus stylirostris. Biochemical analyses of the ingredients revealed that BLM and HFM had low levels of free amino acids (FAA), nucleotides, taurine, protein solubility and small peptide; whereas, KRL had high levels of all except protein solubility. The biochemical profile of PBM was only moderately inferior to that of AFM. FHD had high levels of FAA, protein, and taurine, but low levels of nucleotides and small peptides. Attractability and palatability assessments in shrimp were fairly consistent with the biochemical profile. A 6-week feeding trial using feeds formulated with 20% PBM, no fishmeal and 3% of BLM, AFM, FHD, SLM, or KRL showed that attractability of the feeds was improved by SLM and KRL, but palatability and growth were improved only by KRL.

Gastric Emptying

Gastric Emptying

Effects of Partial Substitution of Fish Meal with Tuna Liver Meal on the Fatty Acid Profile of Nile Tilapia Fry, Oreochromis niloticus

Summary This study was designed to evaluate the effect of diets containing different levels of fish meal (FM) and tuna liver meal (TLM) on the growth performance and fatty acid profiles of Nile tilapia fry, Oreochromis niloticus (initial mean weight: 2.29±0.07 g fish -1 ). Each diet replacing 0, 10, 20, 30, 40, and 50% FM by TLM was randomly allocated to triplicate groups of fish in aquaria for 13 weeks. Results demonstrated that final weight, specific growth rate and protein efficiency ratio of fish fed diets replaced up to 30% TLM were not significantly (P>0.05) different from fish fed the control diet, except for TLM levels of ≥40. There were no significant differences in protein and ash contents in whole-body, while dry matter and lipid contents were significantly affected (P 0.05) between experimental groups. Furthermore, the increase of dietary TLM did not significantly affect the n-3: n-6 ratio in fish flesh.

“Bubbling” or Droplet Regurgitation in Both Sexes of Adult &lt;I&gt;Phormia regina&lt;/I&gt; (Diptera: Calliphoridae) Fed Various Concentrations of Sugar and Protein Solutions

Bubbling behavior or regurgitation is defined as the production of a droplet on the tip of the proboscis. No behavioral differences were observed in the components of the bubbling behavior between the two sexes of adult Phormia regina Meigen (Diptera: Calliphoridae). One of the most interesting behaviors, from a functional standpoint, is the proboscis shaking and proboscis pumping that is always associated with droplet extrusion. Droplets were usually reingested and not dropped on the substrate as reported in some fly species. On a sucrose meal, the average total time the fly spent on bubbling, regardless of sex, was 9.4 min, whereas the average time the droplet was present on the proboscis was 7 min. The number of droplets produced per fly for both sexes was 19.8 for sucrose and 24.6 for liver. The average time to initiate droplet extrusion after a meal by both sexes was 69 min for sucrose and 102 min for the liver meal. Bubbling flies had a statistically significant greater crop volume (7.9 μl on liver and 6.2 μl on sucrose) than nonbubbling flies (4.1 μl on liver and 2.3 μl on sucrose). The latter results place the important functional significance of bubbling or regurgitation on crop volume and the need of flies to eliminate crop water load, thus concentrating crop solute.

Effects of replacing fishmeal with animal by-products meal supplementation in diets on the growth and nutrient utilization of mangrove red snapper

A feeding trial was conducted for 75 d to evaluate the nutritive value of a mixture of animal by-products (MAB) as a possible protein source in diets for juvenile mangrove red snapper, Lutjanus argentimaculatus (mean initial body weight, 30 g). Fish were fed one of five isonitrogenous diets (40% crude protein) replacing 0, 25% (MAB25), 50% (MAB50), 75% (MAB75) and 100% (MAB100) of fish meal protein with similar percentages of MAB. The MAB consisted of 25% cow liver meal, 20% leather meal, 20% meat and bone meal, 15% blood meal, 10% APC (poultry feather meal), 8% poultry manure dried, 1.5% choline and 0.5% chromic oxide. After 75 d of feeding, fish fed with diets MAB50, MAB75 and MAB100 exhibited significantly lower growth performance than that of fish fed with control and MAB25 diets. The optimum level of MAB was estimated to be 23%. Replacement of fish meal by MAB23% showed the following performance: maximum weight gain, 510%; SGR, 2.39% and FCE, 2.83%. The MAB substitution up to 75% of fish meal protein in diets did not show differences in apparent protein digestibility (83.6% for MAB25, 79.2% for MAB50, 78.7% for MAB75) compared with control (83.4%), whereas in MAB100 group digestibility (65.3%) was significantly lower than in other groups. The apparent phosphorus absorption of test diet groups was significantly higher (37.1% for MAB25, 28.5% for MAB50, 55.6% for MAB75 and 54.5% for MAB100) than that of control (11.2%). The levels of protein and ash in the whole body, carcass and viscera increased as MAB substitution in diets increased, whereas lipids and moisture remained consistent among all treatment groups. These results showed that approximately 23% of fish meal protein could be replaced by a mixture of animal by-products for juvenile snapper growing from 30 g to 167 g in 75 d without compromising growth performance and feed efficiency.

APPARENT DIGESTIBILITY OF SELECTED FEED INGREDIENTS IN DIETS FOR MUD CRAB (Scylla paramamosain)

Cultured mud crabs (Scylla spp.) are commonly fed with ‘trash’ fish. Insufficient supply, high cost and variable quality of ‘trash’ fish has lead to a need to develop costeffective and environmentally friendly formulated diets. This study was conducted to determine quality of selected feed ingredients as protein sources in mud crab diets based on their nutrient composition and digestibility coefficients for dry matter (ADMD), crude protein, lipid and energy. The digestibility coefficients for ADMD ranged from 82.46% to 89.20%. Animal-based feedstuffs such as shrimp head, tiny shrimp and squid liver meal had higher ADMD values than fish meal. Of the plant-based feedstuffs, soy bean meal had the highest ADMD values (89.20%) and corn gluten had the lowest (82.46%). Corn gluten had the lowest protein digestibility (78.81%) and soy bean meal had the highest (96.05%). The lowest energy digestibility (71.13%) was obtained in corn gluten meal. Soy bean meal had a higher energy digestibility value (98.48%) than fish meal (85.95%). All animal meal sources had similar energy digestibility values (85.86%—92.09%).

APPARENT DIGESTIBILITY OF SELECTED FEED INGREDIENTS IN DIETS FOR MUD CRAB (Scylla paramamosain)

Cultured mud crabs (Scylla spp.) are commonly fed with ‘trash’ fish. Insufficient supply, high cost and variable quality of ‘trash’ fish has lead to a need to develop costeffective and environmentally friendly formulated diets. This study was conducted to determine quality of selected feed ingredients as protein sources in mud crab diets based on their nutrient composition and digestibility coefficients for dry matter (ADMD), crude protein, lipid and energy. The digestibility coefficients for ADMD ranged from 82.46% to 89.20%. Animal-based feedstuffs such as shrimp head, tiny shrimp and squid liver meal had higher ADMD values than fish meal. Of the plant-based feedstuffs, soy bean meal had the highest ADMD values (89.20%) and corn gluten had the lowest (82.46%). Corn gluten had the lowest protein digestibility (78.81%) and soy bean meal had the highest (96.05%). The lowest energy digestibility (71.13%) was obtained in corn gluten meal. Soy bean meal had a higher energy digestibility value (98.48%) than fish meal (85.95%). All animal meal sources had similar energy digestibility values (85.86%—92.09%).

Behavioral response to selected feed attractants and stimulants in Pacific white shrimp, Litopenaeus vannamei

Nine commercial feeding attractants and stimulants for Litopenaeus vannamei were evaluated by observation of behavioral responses in animals allotted in one Y-maze aquarium apparatus. In the validation phase, fishmeal–Brazilian origin (FMBO); fishmeal–Peruvian origin (FMPO); blood meal (BM), meat and bone meal (MBM), squid meal (SM), fish oil (FO) and fish solubles (FS) were evaluated. There was also a control without stimulatory raw material. The tested materials were included at 3% in neutral gelatin pellets (wet basis). In each behavioral observation, two different ingredients were offered at the same time in equal quantities, being allotted in the end of each chamber's arm. In Phase II after system validation, the following commercial attractants were tested: 80% crude protein (CP) vegetable dried biomass (VDB 80), 68% CP vegetable dried biomass + glutamate + betaine (VDB 68), complex of amino acids (alanine, valine, glycine, proline, serine, histidine, glutamic acid, tyrosine and betaine) with enzymatically digested bivalve mollusk (CAA), condensed fish soluble protein (CFSP), squid liver meal (SLM), betaine (Bet), dried fish solubles–low biogenic amines (DFS LB), dried fish solubles–high biogenic amines (DFS HB) and whole squid protein hydrolysate (WSPH). Attractants were used at a 3% level wet basis with neutral gelatin, without any additional ingredient source available. The best four commercial attractants from this phase (CAA, CFSP, SLM and WSPH) were compared under 0.5% and 1.0% levels. In Phase I of the study, a higher percentage of choices were observed for FMPO and FMBO. BM and FO were the least chosen ingredients. In Phase II, the worst results were observed for Bet, DFS HB and, mainly, for VDB 80 and VDB 68. When two-by-two comparisons were performed, results suggested that CFSP and CAA were the best commercial attractants tested. In the last phase, both CFSP and CAA at 1.0% level were significantly more chosen by shrimp than CFSP (0.5%), SLM (0.5 or 1.0%) or WSPH (0.5 or 1.0%). At both 0.5% and 1.0% levels, shrimp spent a similar amount of time feeding on CFSP and CAA. However, only CAA was statistically better than SLM and WSPH together. Further work is required to better elucidate the chemical drivers of chemostimulation for L. vannamei for each one of the attractants tested.

市販イカ内臓ミールのクロソイ稚魚用飼料としての有効性

市販イカ内臓ミールのクロソイ稚魚用飼料としての有効性

Effect of Partial Replacement of Fish Meal with Squid Liver MealTMin the Diet on Growth and Body Composition of Juvenile Olive Flounder (Paralichthys olivaceus) during Winter Season

We evaluated the effects of the partial dietary replacement of fish meal with squid liver <TEX>$Meal^{TM}$</TEX> on the growth and body composition of juvenile olive flounder Paralichthys olivaceus during the winter season. Twenty-five fish with an initial body weight of 23 g per tank were distributed among 12,250 L flow-through tanks. The experimental diets, which were designated SLM5, SLM1O, and SLM15 diets, were prepared in triplicate along with control diet by replacing 5, 10, and <TEX>$15\%$</TEX> of mackerel fish meal with squid liver <TEX>$Meal^{TM}$</TEX>, respectively. The weight gain and specific growth rate of flounder that were fed the control and SLM5 diets did not differ from those of the fish fed the SLM10 diet, but they were significantly (P<0.05) higher than those of the fish fed the SLM15 diet. The feed efficiency ratios for the flounder that were fed the control, SLM5 and SLM10 diets were significantly (P<0.05) higher than for the fish that were fed the SLM15 diet. However, the protein efficiency ratio for the flounder was not significantly affected by the experimental diets. The crude protein, crude lipid and ash content, and blood chemistry of the flounder were not significantly affected by the experimental diets. Therefore, the replacement of up to <TEX>$10\%$</TEX> of dietary fish meal with squid liver <TEX>$Meal^{TM}$</TEX> can be made without a reduction in growth or a deterioration of the feed efficiency of juvenile olive flounder during the winter season.

Exposure to Retinoic Acids in Non-Pregnant Women Following High Vitamin A Intake with a Liver Meal

Animal liver is a rich source of vitamin A. Due to retinoic acid (RA) metabolites, vitamin A has a teratogenic potential and women are generally advised to avoid or to limit the consumption of liver during pregnancy. In a recent study in non-pregnant female volunteers following single and repeated doses of up to 30,000 IU/day of vitamin A as a supplement, the plasma concentration time curve of all-trans RA acid showed a diurnal-like profile. But, the overall exposure (AUC24h) remained essentially unaltered whereas AUC24h increased linearly with dose for 13-cis and 13-cis-4-oxo RA. The current study in non-pregnant female volunteers showed that a single high vitamin A intake with a liver meal (up to 120,000 IU) exhibited a similar diurnal-like plasma concentration time curve for all-trans RA and its overall exposure remained also unaltered, despite a temporary two-fold increase in peak plasma concentration. Concentrations of 13-cis and 13-cis-4-oxo RA increased several-fold after a liver meal, and exposure (AUC24h) increased three- to five-fold. Pooling our results with data in the literature revealed a linear relation between the mean AUC24h of 13-cis and 13-cis-4-oxo RA and vitamin A intake with liver. Metabolism to all-trans RA of vitamin A with liver seems not to be of safety concern. However, the observed increase of plasma concentrations and the dose-dependent increase in exposure to 13-cis and 13-cis-4-oxo RA support the current safety recommendations on vitamin A intake and suggest that women should be cautious regarding their consumption of liver-containing meals during pregnancy.

Immunological Localization of Mosquito Ovary Ecdysteroidogenic Hormone I and Fruit Fly Insulin Receptor in Adult &lt;I&gt;Phormia regina&lt;/I&gt; (Diptera: Calliphoridae)

The neurohormone ovary ecdysteroidogenic hormone I (OEH I), originally identified from Aedes aegypti (L.), has an effect on mosquito ecdysteroidogenesis. Would there be a similar presence and function in other adult flies, e.g., black blow fly, Phormia regina (Meigen)? One pair of median neurosecretory cells (MNCOEH I) and one pair of lateral neurosecretory cells (LNCOEH I) were immunopositive to OEH I antiserum in the brain of sugar-fed and liver-fed female P. regina. In addition, two pairs of neurosecretory cells (SOGNCOEH I) positive to this antiserum were found in the suboesophageal ganglion only in adult female P. regina at 16, 20, 23, 28, 36, and 72 h after a liver meal. In addition to the positive pairs of MNCOEH I and LNCOEH I in females, there were four more pairs of positive neurons (MSNFNCOEH I) in the region between the MNCOEH I and the esophageal foramen in P. regina males, but not in females. The presence of OEH I in male flies needs further attention as to the function of this hormone in male dipterans. We also found substances positive to Drosophila melanogaster Meigen insulin receptor antiserum located in the corpus cardiacum and the nerves going to the corpus allatum of adult female P. regina at 6 and 30 h after the liver meal, but not to the brain.

Allatotropic activity in the brain of female Phormia regina (Diptera: Calliphoridae)

In Phormia regina, the rate of juvenile hormone (JH) synthesis rises rapidly after the ingestion of an adequate protein meal. In a previous publication we have localized the neurons containing Manduca sexta allatotropin (Mas-AT)-like substances in the brain of P. regina and demonstrated the allatotropic effect of synthetic Mas-AT in sugar-fed flies in vitro. In this current study, we examined the possible role of the brain of P. regina after the fly received a protein meal. In vitro studies showed that the brain releases, at 8 h after a protein meal, a factor(s) with a strong allatotropic effect. This factor(s) stimulates the corpus allatum (CA) to produce 6.9 times more juvenile hormones (JHs) than the control CA. Time course studies showed that the release of this allatotropic factor(s) is temporally controlled. Only the brains collected from flies at 6 and 8 h after the onset of a liver meal release allatotropic factor(s). Injection of anti-Mas-AT antiserum partially suppressed the fly follicle development in vivo. Presence of anti-Mas-AT antiserum decreased the allatotropic effect of the brain released allatotropic factor(s) in vitro. In addition to a Mas-AT-like substance, it is possible that the brains of liver-fed P. regina females may synthesize other allatotropic factors that are chemically unrelated or partially related to Mas-AT, which cannot be recognized/neutralized by our anti-Mas-AT antiserum.

Porcine Intestinal Metabolism of Excess Vitamin A Differs Following Vitamin A Supplementation and Liver Consumption

Vitamin A is a well-established teratogen in all animal species. A number of case reports also suggest a teratogenic potential of vitamin A in humans. A possible teratogenic risk of dietary liver vitamin A intake, the kinetics of vitamin A and its metabolites in humans after intake of either a vitamin A supplement or a liver meal have been studied. Major differences were described for the kinetics of all-trans-retinoic acid (all-trans-RA), which occurred at much higher concentrations after supplementation than after liver consumption. Therefore, we investigated whether the intestine may be responsible for the differences in vitamin A metabolism after supplementation or liver feeding. We found that cytosolic fractions of porcine enterocytes oxidized retinol to all-trans-RA in vitro with a K(m) of 94-96 micromol/L and a V(max) of 7.9-8.6 pmol/(min x mg protein). In an in vivo approach, the portal vein and the central vein (external jugular vein) of a pig were cannulated. In two subsequent experiments, the pig was given a vitamin A supplement or liver. Plasma samples were taken from portal and central veins. Comparison of retinoid levels in these veins indicated that all-trans-RA was already formed from supplemental vitamin A in the intestine and released into the systemic circulation. Two major metabolic pathways were additionally present in the pig, leading to the formation of glucuronides of all-trans-RA and retinol itself. Our results indicate that intestinal metabolism contributes to the elevated levels of all-trans-RA in the systemic circulation after supplementation with vitamin A, but not after consumption of liver.