Health and nutrition of loggerhead sea turtles (Caretta caretta) in the southeastern United States.

Loggerhead sea turtles (Caretta caretta) are opportunistic carnivores that feed primarily on benthic invertebrates and fish. Sea turtle rehabilitation requires provision of a species-specific, balanced diet that supplies nutrition similar to that of a wild diet; this can be challenging because free-ranging loggerheads' diets vary depending on their life stage and geographic location, with predominant prey species dictated by local availability. The goal of this study was to better understand the nutritional needs of subadult and adult loggerheads in rehabilitation. This was accomplished by conducting a retrospective survey of stomach contents identified during gross necropsy of 153 deceased loggerheads that stranded in coastal Georgia, USA. A total of 288 different forage items were identified; the most frequently observed prey items belong to the subphylum Crustacea (N = 131), followed by bony fish (Osteichthyes; N = 45), gastropod mollusks (N = 40), bivalve mollusks (N = 23), and Atlantic horseshoe crabs (Limulus polyphemus; N = 15). The proportions of certain prey items differed significantly with turtle size; adult turtles ate proportionately more gastropods (p = 0.001), and subadults ate proportionately more fish (p = 0.01). Stomach contents information was used to determine common local prey items (blue crab, cannonball jellyfish, horseshoe crab, whelk), which were evaluated for nutritional content. Additionally, we compared hematology and plasma biochemistry profiles (including proteins, trace minerals, and vitamins) between four cohorts of loggerhead turtles, including free-ranging subadults and adults, nesting females, and loggerheads undergoing rehabilitation. This information was applied to inform a regionally specific, formulated diet for tube feeding, and a supplement containing vitamins and minerals for captive loggerheads, to more closely approximate the nutritional content of their natural diet. Assessing the regional and temporal variability in loggerhead diets is an important component in their effective conservation because resultant data can be used to help understand the impacts of environmental perturbations on benthic food webs.

BLOOD FATTY ACID PROFILES OF NERITIC JUVENILE WILD GREEN TURTLES (CHELONIA MYDAS) AND KEMP'S RIDLEYS (LEPIDOCHELYS KEMPII).

Blood fatty acid profiles can indicate an animal's wild-type diet composition and fatty acid status, but have not been reported in sea turtles. Newer technologies allow for fatty acid profiles from very small (less than three drops) samples of whole blood. This study examined whole blood fatty acid profiles of presumably healthy, neritic, juvenile, wild green (Chelonia mydas) (n = 9; 6 males, 3 females) and Kemp's ridley (Lepidochelys kempii) (n = 8; 6 males, 2 females) turtles from North Carolina, USA. Saturated fatty acids, which can be synthesized de novo, consisted primarily of 16:0, although green turtle blood had a higher proportion of 18:0 (P < 0.001) than Kemp's ridleys, while Kemp's ridley blood had higher proportions of 17:0 (P = 0.007), 20:0 (P = 0.03), 22:0 (P= 0.002), and 24:0 (P < 0.001) as compared with green turtles. Total monounsaturated w7 fatty acids, which can be synthesized de novo or may be diet derived, were higher in Kemp's ridleys and predominantly in the form of 16:1 and 18:1w7 fatty acids. Kemp's ridley blood had more than double the relative proportion of 16:1w7 as compared with green turtles (P= 0.03). Green turtles had higher levels of 18:2w6 than Kemp's ridleys (P= 0.02). In both turtle species, 20:4w6 was detected, despite predicted low dietary proportions, suggesting bioconversion from precursors. Finally, green turtles had higher levels of 18:3w3 compared with Kemp's ridleys, while Kemp's ridleys had higher proportions of 20:5w3 compared with green turtles (P < 0.001, = 0.007, respectively). Whole blood fatty acid profiles generally correlate to previous work with lipid depots, supporting the use of this less invasive methodology to advance the understanding of fatty acid nutrition of sea turtles. These data can be used to assess and guide nutrition and health programs for sea turtles under human care.

Effect of varying dietary starch and fiber levels and inoculum source (mule deer vs. dairy cow) on simulated rumen fermentation characteristics.

This study measured starch and fiber digestion and microbial fermentation of three commercial exotic animal feeds using mule deer (MD) or dairy cow (DC) rumen inoculum. Diets were formulated to provide either high starch/low fiber (based on neutral detergent fiber fraction; NDF) with either alfalfa (diet A) or grain and oilseed byproducts (diet B) as the major fiber sources or low starch/high NDF (diet C). An initial batch culture incubation was run with diets inoculated with each rumen inoculum (n = 6; N = 36) over a 48 hr period with samples taken at different hour points for ammonia, pH, lactate, and volatile fatty acids (VFA). A second experiment was conducted where two continuous culture incubations (MD or DC) were run with six single-flow polycarbonate fermentation vessels per dietary treatment. Diets were fed two times a day over an 8-day period and sampled for ammonia, pH, and VFA before and after feeding on the last 3 days. On day 8, fermenter and effluent contents were collected and analyzed for nitrogen, dry matter digestibility (DMD), and organic matter digestibility (OMD). OMD was greater in MD (P = 0.02) and DMD tended to do the same (P = 0.06), but there were no differences due to diet (P > 0.05). Ammonia concentration was greater in DC (P < 0.01), and diets A and B had greater concentrations than diet C (P < 0.01). The greater digestibility, higher acetate:propionate (A:P) ratio and increased lactate levels prior to feeding likely led to diet C having a lower pH than diet A (6.59 vs. 6.66, respectively; P < 0.01) and led the tendency of A to be lower than C after feeding (P = 0.08). A:P ratio was greater in DC than MD before and after feeding (P < 0.01) and was greater in diet C than diets A or B (P < 0.01). Total VFA production tended to be greater in diets B and C in DC (P = 0.06). Rumen fluid source did affect fermentation. Increasing fiber level did not negatively affect fermentation and may increase OMD by removal of negative associative affects by starch on cellulolytic bacteria.

Absorption and ocular deposition of dietary lutein in marine mammals.

Cataracts and ocular disease are common lesions of marine mammals in zoological collections. Lutein, an oxygenated carotenoid, may have therapeutic or prophylactic effects on ocular disorder. Therefore, this study examined the ability of marine mammals to absorb dietary lutein. Two preliminary trials examined lutein in two forms (beadlet or ester) in a small sample size of marine mammals representing pinnipeds and cetaceans. Lutein was fed daily in tablets providing 0.89-3.6 mg lutein/kg body weight(0.75) per day for 15 days to 2 years. A third study was conducted using lutein beadlet fed at 3.6 mg lutein/kg body weight(0.75) per day for 15-21 days. Blood was analyzed for lutein pre- and postsupplementation. In the preliminary trials, lutein beadlet was observed to result in greater blood lutein levels than lutein esters, and cetaceans had more noticeable responses than pinnipeds. In Study 3, serum lutein and zeaxanthin increased postsupplementation in beluga whales (P < 0.05), and serum lutein tended to increase postsupplementation in dolphins (P < 0.10), but little change was seen in serum lutein in pinnipeds or manatee. Opportunistic retinal samples demonstrated some detectable lutein in the retina of a dolphin and several harp seals. The lutein levels in dolphins after supplementation are similar to those reported in free-ranging animals. Ocular lutein in harp seals demonstrates that ocular deposition occurs despite low circulating lutein levels.

Avian iron storage disease: variations on a common theme?

Many frugivorous avian species kept in captivity develop iron storage disease (ISD) as indicated by high concentrations of hepatic iron and hemosiderin deposits in hepatocytes or phagocytes. In several susceptible species fed diets containing moderate levels of iron, ISD develops because of an inability to match rates of iron absorption to tissue needs. Evidence suggests that the pathophysiologic basis of excess iron absorption is due to high levels of expression of divalent metal transporter-1 that transports iron into enterocytes in the proximal intestine, and ferroportin that exports iron to the circulation. The regulatory basis for this inability to sufficiently down-regulate iron absorption is unknown, but disruptions in the hepcidin-ferroportin axis are likely candidates based on recent research in humans and laboratory rodents. It is likely that ISD-susceptible avian species evolved on foods that were very low in bioavailable iron, so there was strong selection pressure for the efficient capture of the small amount of dietary iron but low selection pressure for preventing iron toxicities. Thus, the transporters and regulatory networks for iron absorption seem to be heavily skewed toward iron storage even when food items that are high in iron are consumed. Infections, trauma and neoplasias that trigger an acute phase response may exacerbate ISD in susceptible species and may be the primary cause in species that are normally resistant to ISD (i.e., those that are normally able to shut down intestinal iron absorption when iron stores are replete). The evolutionary basis that resulted in some avian species to be susceptible to ISD (e.g., dietary cause) seems to differ from many inherited ISD disorders in humans that are thought to have evolved to bolster protection against infectious diseases. However the evolutionary basis of ISD in other mammalian species might be more similar to that in ISD-susceptible avian species.

Palatability and apparent total tract macronutrient digestibility of retorted black soldier fly larvae-containing diets and their effects on the fecal characteristics of cats consuming them.

There is a growing interest in using black soldier fly larvae (BSFL) due to its supposed sustainability and nutritional qualities. Because little research has been conducted to evaluate the use of BSFL in cats, our objective was to determine the palatability and apparent total tract macronutrient digestibility (ATTD) of BSFL-containing canned diets and the fecal characteristics of healthy adult cats consuming them. First, three palatability tests were conducted to compare the following diets: 1) diet with poultry byproduct meal (PBPM) and chicken serving as the primary protein sources (control) vs. diet with BSFL meal replacing PBPM (BSFL meal); 2) control vs. diet with whole BSFL replacing some PBPM and poultry fat (BSFL whole); and 3) control vs. diet with BSFL oil replacing poultry fat (BSFL oil). All diets were formulated to meet Association of American Feed Control Officials nutrient profiles for adult cats and were produced using a still retort. A paired t-test was conducted to analyze data from each palatability test, with a higher (P < 0.05) consumption ratio being observed for BSFL meal (1.93:1), BSFL whole (2.03:1), and BSFL oil (1.57:1). Second, 32 adult cats (20 females and 12 males; BW: 4.19 ± 0.55 kg; age: 3.3 ± 0.38 yr) were used in a completely randomized design study composed of a 21-d baseline period and a 70-d experimental period. Cats consumed the control diet during the baseline and were then allotted to one of four experimental diets (n = 8 per group): 1) control, 2) BSFL meal, 3) whole BSFL, and 4) BSFL oil. Fecal samples were collected after baseline and experimental periods for ATTD and fecal characteristic analysis. Fecal output was higher (P < 0.05) and fecal dry matter percentage was lower (P < 0.05) in cats fed BSFL meal than those fed BSFL oil. Organic matter, crude protein (CP), and energy ATTD were lower (P < 0.05) in cats fed BSFL meal than those fed BSFL oil or control. CP and energy ATTD were lower (P < 0.05) in cats fed BSFL whole than those fed BSFL oil. A few serum metabolites were affected by diet (P < 0.05) but remained within reference ranges. Hematology was not affected by diet (P > 0.05). Overall, our results suggest that BSFL-containing diets are palatable and do not negatively affect fecal characteristics or serum chemistry but may have slightly lower nutrient digestibilities in adult cats.

The pet food industry is interested in black soldier fly larvae (BSFL) because of its supposed sustainability and nutritional qualities. BSFL has not been well tested in cats, so our objective was to determine the palatability and apparent total tract macronutrient digestibility (ATTD) of BSFL-containing canned diets and how they affected the fecal characteristics of adult cats. Palatability tests were conducted to compare diets containing BSFL meal, whole BSFL, or BSFL oil against a poultry-based control. Higher consumption ratios were observed for all BSFL-containing diets. A second study determined the digestibility of BSFL-containing diets and how they affected fecal characteristics. Cats were allotted to a control diet or diets containing BSFL meal, whole BSFL, or BSFL oil. Fecal output was higher and fecal dry matter percentage was lower in cats fed BSFL meal than those fed BSFL oil. Organic matter, crude protein (CP), and energy ATTD were lower in cats fed BSFL meal than those fed BSFL oil or control. CP and energy ATTD were lower in cats fed whole BSFL than those fed BSFL oil. Overall, BSFL-containing diets were shown to be palatable and did not negatively affect fecal characteristics, but reduced nutrient digestibilities in adult cats.

Evaluation of an alternative to feeding whole frozen fish in belugas (Delphinapterus leucas).

Feeding fish to captive piscivores can be challenging owing to cost, availability, variability in nutrient, and caloric composition, as well as handling and storage concerns. This trial evaluated the response of three belugas to being fed Fish Analog, an alternative to frozen fish. Body condition, gut transit time, serum chemistry and metabolic hormone analytes, immune function, and behavioral motivation were the dependent variables. Belugas (n=3) were fed various levels of Fish Analog (0-50%) over a 6-month period, and follow-up studies were conducted to further examine several dependent variables. When provided in gradually increasing amounts, belugas consumed the Fish Analog, with only minor fecal consistency changes and without behavioral responses indicative of gastric discomfort. Axillary girth and blubber thickness were positively correlated, and did not differ significantly with changes in the percentage of Fish Analog fed. Individual animal variation in initial passage time, some serum chemistry analytes, and immune function differences were noted following feeding of Fish Analog. Feeding Fish Analog reduced blood n9 fatty acids compared with captive belugas fed no Fish Analog. Feeding a DHA-enriched Fish Analog increased several n3 fatty acids, including eicosapentaenoic acid, but not DHA, compared with whales fed no Fish Analog or non-DHA-enriched Fish Analog. Fish Analog was shown to be a viable alternative to feeding fish at up to 50% of the dietary caloric density.

Serum chemistry comparisons between captive and free-ranging giraffes (Giraffa camelopardalis).

Serum chemistry analyses were compared between captive and free-ranging giraffes (Giraffa camelopardalis) in an attempt to better understand some of the medical issues seen with captive giraffes. Illnesses, including peracute mortality, energy malnutrition, pancreatic disease, urolithiasis, hoof disease, and severe intestinal parasitism, may be related to zoo nutrition and management issues. Serum samples were collected from 20 captive giraffes at 10 United States institutions. Thirteen of the captive animal samples were collected from animals trained for blood collection; seven were banked samples obtained from a previous serum collection. These samples were compared with serum samples collected from 24 free-ranging giraffes in South Africa. Differences between captive and free-ranging giraffes, males and females, and adults and subadults were analyzed by using a 2 x 2 x 2 factorial and Fisher's least significant difference for mean separation; when necessary variables were ranked and analyzed via analysis of variance. Potassium and bilirubin concentrations and alanine aminotransferase (ALT) activities were different between captive and free-ranging giraffes, but all fell within normal bovid reference ranges. The average glucose concentration was significantly elevated in free-ranging giraffes (161 mg/dl) compared with captive giraffes (113 mg/dl). All giraffes in this study had glucose concentrations higher than bovine (42-75 mg/ dl) and caprine (48-76 mg/dl) reference ranges. Differences were also seen in lipase, chloride, and magnesium though these findings are likely not clinically significant. There were no differences detected between sexes. Adults had higher concentrations of potassium, total protein, globulins, and chloride and higher gamma glutamyltransferase activities, whereas subadults had higher concentrations of phosphorus. Within the captive group, nonimmobilized animals had higher concentrations of total protein and globulins. Captive giraffe diets need further investigation to determine if the differences seen in this study, especially glucose and bilirubin concentrations and ALT activities, may result in some health problems often seen in captive giraffes.

Digestibility and safety of dry black soldier fly larvae meal and black soldier fly larvae oil in dogs.

Two trials were conducted to assess the acceptance, safety and digestibility of diets containing various inclusion levels of partially defatted black soldier fly (Hermetia illucens) larvae (BSFL) meal and BSFL oil by dogs. In trial 1, 5 extruded diets were evaluated for acceptance in adult Beagle dogs (n = 20; 10 male, 10 female) during a 48-hr period. Diets contained graded levels of BSFL meal (5.0%, 10.0%, and 20.0%), or graded levels of BSFL oil (2.5% and 5.0%), and all diets were well accepted. Thus, a digestibility trial (trial 2) was run with 56 adult dogs (16 male, 40 female) allocated into 7 dietary treatments; dogs were offered an extruded control diet containing no BSFL meal or oil, or extruded diets where BSFL meal partially replaced poultry by-product meal and corn meal at dietary levels of 5%, 10%, or 20% inclusion, or diets with BSFL oil partially replacing poultry fat at a 1:1 ratio at levels of 1%, 2.5%, or 5% inclusion. The treatment diets were fed for 28 d, during which time dogs were monitored for health (via physical examinations, clinical observations, and blood chemistry and hematology) and ingredient evaluation (via body weight, feed consumption, stool observation, and fecal nutrient apparent total tract digestibility). There were no significant differences in body weight or food consumption between treatment groups (P > 0.05) and daily observations indicated that the general health of the animals was maintained throughout the study. Stool quality was maintained at 3.2 to 3.4 (on a 5-point scale with a score of 1 being watery diarrhea and a score of 5 being hard, dry, and crumbly) per treatment group over the fecal observation period (days 22 to 27), indicating a well formed, sticky stool. All group mean hematology and blood chemistry parameters remained within normal limits for dogs. Apparent total tract digestibility of dry matter, protein, fat, and calories was not affected by treatment (P > 0.05). In general, amino acid digestibility was not impacted by treatment although some minor changes were observed. Apparent total tract digestibility was high for all nutrients examined. Overall, it was concluded that BSFL meal and BSFL oil are well tolerated by dogs and their consumption results in no impact to physiology that would be concerning. Based on these data, BSFL meal and oil did not affect general health and could be included safely in dog diets.

Amino acid digestibility and digestible indispensable amino acid score-like values of black soldier fly larvae fed different forms and concentrations of calcium using the precision-fed cecectomized rooster assay.

Black soldier fly larvae (BSFL) are an alternative protein source for animals, including dogs and cats. Dietary calcium source is an essential nutrient for BSFL development in the pupal stage. Calcium carbonate (CaCO3) and calcium chloride (CaCl2) are common calcium sources but differ in solubility, acid-binding capacity, and calcium concentration. A high calcium concentration in BSFL may affect how well nitrogen and amino acids (AA) are digested by animals consuming them, thereby affecting feed conversion efficiency. Our objective was to determine the effects of dietary calcium form and concentration on nutrient composition, AA digestibility, and digestible indispensable amino acid score (DIAAS)-like values of BSFL intended for use in animal feeds using the precision-fed cecectomized rooster assay. All BSFL tested in this study were harvested at 18 d after hatch. Industry standard rearing conditions were maintained and a commercial layer ration was fed to all BSFL until 11 d post-hatch. From day 11 to 18, BSFL were fed a combination of distiller's dried grains with solubles from a distillery, bakery byproduct meal, and varied calcium sources. All BSFL diets contained 0.2% calcium in the basal diet plus additional calcium in the following amounts and forms: BSFLA: 1.2% CaCl2, BSFLB: 1.2% CaCO3, BSFLC: 0.75% CaCO3, and BSFLD: 0.6% CaCO3 + 0.6% CaCl2. On day 18, BSFL were washed and frozen. Prior to the rooster assay, BSFL were lyophilized and ground. In total, 16 cecectomized roosters (4 roosters per substrate) were randomly assigned to test substrates. After 24 h of feed withdrawal, roosters were tube-fed 20 g of test substrates. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using five additional cecectomized roosters. All data were analyzed using a completely randomized design and the GLM procedure of SAS 9.4. Nutrient and AA digestibilities were not different among substrates. DIAAS-like values were calculated to determine protein quality according to the Association of American Feed Control Officials nutrient profiles and National Research Council recommended allowances for dogs and cats. Although AA digestibilities did not differ, those containing CaCO3 generally had higher DIAAS-like reference values than the diet containing CaCl2 alone (BSFLA). Aromatic AA (Phe + Tyr) and sulfur AA (Met + Cys) were often first-limiting AA. Our results suggest that calcium sources fed to BSFL did not affect AA digestibility and protein quality.

Biochemical and physiological observations in meerkats (Suricata suricatta) at two zoos during a dietary transition to a diet designed for insectivores.

This research (involving two separate institutions) assessed the serum chemistries and body weights of meerkats (Suricata suricatta) over a 6-10-week feeding trial to determine the acceptability of a commercially available manufactured diet intended for the feeding of insectivorous animals. Five animals at two zoos were heavier than desired and otherwise healthy at the start of the studies. Measurements of blood chemistries including cholesterol and cell blood count remained within physiologic expected ranges throughout the short-term study. Plasma and serum amino acid levels also remained within normal expected ranges, except taurine, which was much higher than predicted, although there were no significant changes in taurine over time. After initiation of the 6-week trial, these trials were extended for longer-term evaluation of animals in regards to body weight maintenance. In the long-term study, some individuals were restricted in their access to diet, and achieved a beneficial weight loss while maintaining good health. Approximate dietary consumption for captive meerkats in our study averaged 32-44 g, or calculated 92-127 kcal GE/meerkat*day (83-114 kcal ME/meerkat*day), and weight loss of animals at one institution of 10.4% was accomplished over 151 days from day 0, at approximately 30 g, or calculated 86 kcal GE/meerkat*day (78 kcal ME/meerkat*day).

Serum concentration comparisons of amino acids, fatty acids, lipoproteins, vitamins A and E, and minerals between zoo and free-ranging giraffes (Giraffa camelopardalis).

Serum concentrations of amino acids, fatty acids, lipoproteins, vitamins A and E, and minerals in zoo giraffes (Giraffa camelopardalis) were compared to values obtained from free-ranging giraffes in an effort to identify potential nutritional differences in the zoo population. Zoo giraffes have a specific set of maladies that may be nutritionally related, including peracute mortality, energy malnutrition, pancreatic disease, urolithiasis, hoof disease, and severe intestinal parasitism. Dietary requirements for giraffes are not known; invasive studies used with domestic animals cannot be performed on zoo animals. Though domestic animal standards are often used to evaluate nutritional health of exotic animals, they may not be the most appropriate standards to use. Serum samples from 20 zoo giraffes at 10 zoological institutions in the United States were compared to previously collected samples from 24 free-ranging giraffes in South Africa. Thirteen of the zoo animal samples were collected from animals trained for blood collection, and seven were banked samples obtained from a previous serum collection. Dietary information was also collected on each zoo giraffe; most zoo giraffe diets consisted of alfalfa-based pellets (acid detergent fiber-16), alfalfa hay, and browse in varying quantities. Differences between zoo and free-ranging giraffes, males and females, and adults and subadults were analyzed with the use of a 2 x 2 x 2 factorial and Fisher's Least Significant Difference (LSD) for mean separation. Of the 84 parameters measured, 54 (60%) were significantly different (P < or = 0.05) between zoo and free-ranging giraffes. Nine (11%) items were significantly different (P < or = 0.05) between adult and subadult animals. Only one parameter, sodium concentration, was found to be significantly different (P < or = 0.05) between genders. Further investigation in zoo giraffe diets is needed to address the differences seen in this study and the potentially related health problems.

Moderate zinc restriction affects intestinal health and immune function in lipopolysaccharide-challenged mice.

Zinc (Zn) is an essential nutrient that affects immune function, especially within the digestive system, although the underlying mechanisms are not well understood. This study examined the effects of short-term moderate Zn restriction on intestinal health and immune function in lipopolysaccharide (LPS)-challenged mice through plasma cytokine profiling and histological evaluation of intestinal tissue sections. Adult male mice were fed with a Zn-adequate (40 ppm) or a Zn-marginal (4 ppm) diet for 4 weeks, and then a bacterial challenge was simulated by intraperitoneal injection of LPS (10 microg/g body weight [BW]) or saline (control). BW was recorded weekly, and feed intake was recorded daily over the last week. Voluntary locomotor activity was assessed 6 and 24 h after the challenge. Plasma and tissues were collected 0, 6 or 24 h after the challenge for analysis. Histological analysis of intestinal samples included evaluation of villi length and width, lamina propria (LP) width, crypt depth and intraepithelial as well as LP leukocyte numbers. Plasma was analyzed for IL-1beta, IL-4, IL-6, IL-10, IL-12p40, IL-12p70, interferon gamma and tumor necrosis factor alpha. Diet did not affect BW and feed intake. The LPS challenge led to decreased voluntary locomotor activity (P<.05). Moderate Zn restriction led to greater leukocyte infiltration in the LP after the LPS challenge (P<.05) and higher plasma IL-6 and IL-10 levels 24 h after the LPS challenge (P<.01). Results indicate that Zn status impacts intestinal responses to LPS through modulation of the cytokine response and leukocyte recruitment, and this impact is evident even with short-term (4 weeks) moderate Zn restriction.

Maternal and dietary carotenoids interactively affect cutaneous basophil responses in growing chickens (Gallus gallus domesticus).

This trial examined effects of lutein supplied from maternal (i.e., in ovo) and dietary routes on cutaneous basophil hypersensitivity responses in chickens. Chicks hatched from one of two in ovo carotenoid levels (n=100/level; carotenoid-replete or carotenoid-deplete eggs) were fed one of two diet lutein levels (0 or 40 mg diet lutein/kg diet). At 14 d post-hatch, phytohemagglutinin (PHA) was injected into the wing web, and thickness and leukocyte populations were measured at 0 to 48 h. PHA increased wing web thickness at 4 to 48 h post-PHA (p<0.05), and the swelling response was most related to macrophage numbers in the wing web. Swelling occurred more rapidly in chicks from carotenoid-deplete eggs (p<0.05), but eventually reached a greater thickness in chicks from carotenoid-replete eggs (p<0.05). Differences in leukocyte infiltration occurred due to diet and in ovo carotenoid exposure, and indicate that pre- and post-hatch carotenoid exposure had additive or synergistic effects on the PHA-induced wing web response. Evaluation of the cellular contents of the injection site is a much better indicator of the immunomodulatory effects of lutein than measurements of the amount of swelling.

General principles of nutrition for the newly hatched chick.

Nutrition of the newly hatched chick is complex and requires an understanding of the wild-type feeding strategy of the species, the known nutrient requirements of birds, and appropriate application to the species in question. Next, composition of available food items, appropriate physical form, volume and frequency of food items, and desired end results (eg, appropriate fledging weight, ability to successfully find prey items or be socialized for human interactions, etc) need to be considered to provide the highest chance of successful fledging. There are several excellent resources to help guide the practical aspects of rearing chicks (eg, Gage and Duerr), in addition to nutritional resources to guide a better understanding of the fundamentals of avian nutrition (eg, Klasing).

Carotenoids from in ovo or dietary sources blunt systemic indices of the inflammatory response in growing chicks (Gallus gallus domesticus).

Lutein, a dihydroxycarotenoid, has antioxidant and immunomodulatory potential. Two 2 x 2 x 2 factorial designs examined effects of carotenoids during in ovo embryogenesis and, in the diet posthatch, on the systemic inflammatory response to lipopolysaccharide (LPS). In both trials, breeder hens were fed a carotenoid-replete (40 mg lutein/kg) or a carotenoid-deplete diet, eggs were collected, and chicks were hatched from carotenoid-deplete or carotenoid-replete eggs. Meat-type chicks (n = 160 and n = 144, respectively) were then fed diets containing 0 or 40 mg lutein/kg diet and either injected or not injected with LPS. LPS injection increased plasma haptoglobin and Zn (P < 0.01) and reduced plasma Fe and Cu (P < 0.01). Chicks hatched from carotenoid-deplete eggs had greater changes in plasma Fe and S post-LPS than chicks hatched from carotenoid-replete eggs (P < 0.05 for each). Compared with chicks fed 40 mg lutein/kg diet, chicks fed 0 mg lutein had greater body weight losses and higher plasma haptoglobin and relative thymus, bursa, and spleen weights post-LPS (P < 0.05). Data suggest that a lack of carotenoid exposure, either in ovo or posthatch, increases parameters of systemic inflammation.

The effect of an acute phase response on tissue carotenoid levels of growing chickens (Gallus gallus domesticus).

Plasma, liver and skin carotenoids decrease following infectious disease challenges. Since these challenges often involve substantial host pathology and chronic immune responses, the mechanism underlying altered carotenoid deposition is unclear. Therefore, changes in tissue carotenoid levels were examined during an acute phase response induced by lipopolysaccharide (LPS) or interleukin-1 (IL-1). In two experiments, chicks were hatched from carotenoid-deplete eggs (n=28, n=64, respectively) and fed 0, 8 or 38 mg carotenoids (lutein+canthaxanthin)/kg diet. For chicks fed 38 mg carotenoids, but not those fed 0 or 8 mg, LPS generally reduced plasma lutein, canthaxanthin and total carotenoids (P<0.05), and liver lutein, zeaxanthin, canthaxanthin and total carotenoids (P<0.05). Additionally, LPS reduced thymic total carotenoids (P=0.05) and increased thymocyte lutein (P=0.07), zeaxanthin (P=0.07) and total carotenoids (P=0.07). Finally, LPS increased bursal canthaxanthin (P<0.01), but had no effect on shank carotenoids (P>0.5). In chicks hatched from carotenoid-replete eggs (n=36) and fed dietary lutein (38 mg/kg diet), LPS reduced plasma and liver zeaxanthin and liver total carotenoids (P<0.05); IL-1 reduced plasma and liver lutein, zeaxanthin and total carotenoids (P<0.05). Therefore, an acute phase response plays a role in reduced tissue carotenoids during infectious disease.

Maternal carotenoid status modifies the incorporation of dietary carotenoids into immune tissues of growing chickens (Gallus gallus domesticus).

Carotenoids provide pigmentation to avian species, and also have immunomodulatory potential, although experimental results are often inconsistent. Therefore, dietary carotenoid deposition into immune tissue of growing chicks was examined in relation to their maternal carotenoid status (i.e., yolk carotenoid level). Single-comb white leghorn chicks were hatched from carotenoid-replete (C+) or carotenoid-deplete (C-) eggs. For 4 wk posthatch, chicks were fed diets whose carotenoid level ranged from 0 to 38 mg total carotenoid/kg. Carotenoid additions consisted of lutein + canthaxanthin at a ratio of 4:1. After 4 wk, the carotenoid concentration of thymus, bursa, liver, plasma and shank epithelium was measured by HPLC. Egg yolk-derived carotenoids were detectable in chicks fed 0 dietary carotenoids for 4 wk. Chicks hatched from C+ eggs had significantly greater tissue lutein, zeaxanthin and/or canthaxanthin for all tissues (P < 0.05), compared to chicks hatched from C- eggs. Only bursa carotenoids were not dependent on chick diet (P = 0.24); for all other tissues, C+ chicks incorporated dietary carotenoids in a dose-dependent manner (P < 0.01), whereas C- chicks never achieved the same level of carotenoid incorporation. This study demonstrated the importance of maternal carotenoid status on incorporation of yolk- and diet-derived tissue carotenoids in an avian model, and may explain some variability in carotenoid-based research, given that maternal carotenoid status is rarely controlled.

Adult cockatiels (Nymphicus hollandicus) at maintenance are more sensitive to diets containing excess vitamin A than to vitamin A-deficient diets.

The purpose of this experiment was to examine the physiological responses of adult cockatiels at maintenance to dietary vitamin A (VA) concentrations, and to identify concentrations associated with deficiency and toxicity. Adult cockatiels at maintenance (n = 22, 2-3 y of age) were fed a diet of 0, 600, 3000 or 30,000 microg VA/kg (0, 2000, 10,000 or 100,000 IU), and monitored for signs of VA deficiency or toxicity for up to 706 d. The analyzed diet concentrations were 0, 835, 2815 and 24,549 microg/kg, respectively. After 269 d, birds fed the 30,000 microg/kg VA diet had greater plasma retinal concentrations, markedly intensified vocalization patterns, pancreatitis and multifocal accumulation of lymphocytes in the lamina propria of the duodenum compared to birds fed the 600 microg/kg diet (P < 0.05). The 3000 microg/kg VA diet induced increased plasma retinol, splenic hemosiderosis and altered vocalization patterns (P < 0.05), although not as striking as those induced by the 30,000 microg/kg VA diet. The secondary antibody response was reduced after 225 d and vocalization patterns were altered in birds fed 0 microg/kg VA (P < 0.05), but after almost 2 y there were no changes in body condition, plasma retinol, organ pathology or classical signs of deficiency such as squamous metaplasia of nasal epithelia. Thus, adult cockatiels at maintenance were more susceptible to VA toxicity than to VA deficiency and concentrations > or = 3000 microg VA/kg diet can cause toxicity. It is possible that disturbances in VA nutrition contribute to the widespread incidence of behavioral problems reported in companion birds.