Dry Diet Research Articles

Dietary total aromatic amino acid requirement and tyrosine replacement value for phenylalanine for fingerling Oreochromis niloticus (Linnaeus)

This study was conducted to determine the dietary total aromatic amino acid requirement and tyrosine replacement value for phenylalanine for fingerling Oreochromis niloticus by conducting two 8-week experiments. In experiment I, phenylalanine requirement was determined by feeding test diets (350 g kg–1 CP; 16.72 kJ g–1 GE) with graded levels of phenylalanine (4, 6.5, 9, 11.5, 14 and 16.5 g kg–1 dry diet) at a constant level (10 g kg–1) of dietary tyrosine to triplicate groups of fish (1.65 ± 0.09 g). Quadratic analyses of absolute weight gain (AWG), protein deposition (PD%) and phenylalanine retention efficiency (PRE%) indicated the requirement at 12.1 g kg–1 dry diet. In experiment II, six diets with different levels of L-tyrosine (2.0, 4.0, 6.0, 8.0, 10.0 and 12.0 g kg–1 dry diet) with 12.1 g kg–1 phenylalanine as determined in experiment I fixed in all the test diets were fed to fish (1.67 ± 0.17 g) to determine the tyrosine requirement under same conditions. Quadratic regression analysis of AWG, PD and PRE demonstrated the tyrosine requirement at 8.5 g kg–1 dry diet, corresponding to 24.2 g kg–1 of dietary protein. Based on the above data, the total aromatic amino acid requirement was found to be 20.6 g kg–1 of dry diet, corresponding to 58.8 g kg–1 of dietary protein, and tyrosine replacement value for phenylalanine was found to be 37% on a molar basis.

Body condition loss during the dry period: Insights from feeding behavior studies

Body condition change during the dry period (ΔBCS) has been associated with a myriad of transition cow diseases. We used data from 3 studies to assess the relationship between ΔBCS, feeding behavior, and body condition score (BCS) at dry-off. We also studied the mediation effect that dry matter intake (DMI) has on ΔBCS and the association between dry period feeding time and DMI. A total of 100 parous cows were enrolled in 3 studies to investigate differences in dry period diet on behavior, health, and performance pre- and postcalving. Body weight was measured and BCS was assessed by the same trained observer after dry-off and 1 wk from calving date. The ΔBCS was calculated by subtracting the BCS at calving minus the BCS at dry-off. The BCS at dry-off was categorized as overconditioned (≥3.5) or not overconditioned (<3.5); no cows had a BCS <2.75. Feeding behavior data were collected using electronic feed bins. Parity at dry-off (median = 2; min = 1, max = 6) and 305-d milk production (mean = 10,235 kg, SD = 1,625 kg) from the previous lactation were considered. Data sets were split into 2 time periods: d -56 to -22 (early) and -21 to 0 (late) in relation to calving. Selected feeding behaviors (DMI, DMI as a percentage of body weight, and feeding time) were used to evaluate the associations between each feeding behavior and BCS at dry-off in each period using mixed linear regression models. Each model included the following covariates: parity, previous 305-d milk yield, and trial treatment. Experimental day was included as random slope, and cow was included as random intercept. A mediation analysis was used to evaluate the potential causal direct effect of BCS at dry-off on ΔBCS and the potential indirect effect mediated by differences in DMI. The BCS at dry-off was associated with changes in feeding behavior, such that overconditioned cows had lesser daily DMI and feeding time during the early and late dry periods compared with not overconditioned animals. We also noted an effect of previous 305-d milk yield on DMI; cows that produced more milk had greater DMI throughout the dry period. The ΔBCS was only partially mediated by DMI, and BCS at dry-off still had a direct effect on ΔBCS. This result indicated that mechanisms other than DMI were associated with BCS loss during the dry period. Feeding time correlated weakly and moderately with DMI during the early and late dry periods, respectively. To conclude, strategies to improve intake during the dry period should take dry-off BCS into account or, preferably, efforts should be made to minimize the number of overconditioned cows at the end of lactation.

Towards establishing no observed adverse effect levels (NOAEL) for different sources of dietary phosphorus in feline adult diets: results from a 7-month feeding study.

High dietary phosphorus (P), particularly soluble salts, may contribute to chronic kidney disease development in cats. The aim of the present study was to assess the safety of P supplied at 1 g/1000 kcal (4184kJ) from a highly soluble P salt in P-rich dry format feline diets. Seventy-five healthy adult cats (n 25/group) were fed either a low P control (1·4 g/1000 kcal [4184kJ]; Ca:P ratio 0·97) or one of two test diets with 4 g/1000 kcal (4184 kJ); Ca:P 1·04 or 5 g/1000 kcal (4184kJ); Ca:P 1·27, both incorporating 1 g/1000 kcal (4184 kJ) sodium tripolyphosphate (STPP) - for a period of 30 weeks in a randomised parallel-group study. Health markers in blood and urine, glomerular filtration rate, renal ultrasound and bone density were assessed at baseline and at regular time points. At the end of the test period, responses following transition to a commercial diet (total P - 2·34 g/1000 kcal [4184kJ], Ca:P 1·3) for a 4-week washout period were also assessed. No adverse effects on general, kidney or bone (skeletal) function and health were observed. P and Ca balance, some serum biochemistry parameters and regulatory hormones were increased in cats fed test diets from week 2 onwards (P ≤ 0·05). Data from the washout period suggest that increased serum creatinine and urea values observed in the two test diet groups were influenced by dietary differences during the test period, and not indicative of changes in renal function. The present data suggest no observed adverse effect level for feline diets containing 1 g P/1000 kcal (4184 kJ) from STPP and total P level of up to 5 g/1000 kcal (4184 kJ) when fed for 30 weeks.

Evaluating the dietary taurine requirement of hybrid striped bass, (Morone chrysops x M. saxatilis)

A dietary requirement for the sulfonic acid taurine has been documented in many marine species. However, it has not been well studied in hybrid fish with freshwater and marine genes, such as the hybrid striped bass (Morone chrysops x M. saxatilis). Therefore, an 8-week feeding trial was conducted to evaluate the effects of various levels of dietary taurine on growth performance, health, and body composition of juvenile hybrid striped bass. Four diets were formulated from practical ingredients and supplemented with DL-methionine at 0.54% of dry weight to meet the hybrid striped bass' established total sulfur amino acid requirement of 1.0% of dry diet, and taurine was supplemented incrementally at 0, 0.5, 1, and 2% of dry weight. Two additional diets were prepared without DL-methionine supplementation to be marginally deficient in methionine (0.49% by weight) and either supplemented with or without taurine at 1% dry weight to evaluate the potential interactions between methionine and taurine. Diets containing increment levels of taurine were determined to show no significant (P > .05) differences in terms of weight gain, feed efficiency (FE), whole-body composition, hepatosomatic index (HSI), intraperitoneal fat ratio (IPF ratio), or muscle yield. However, hybrid striped bass fed the methionine-deficient diets had significantly (P < .05) reduced percentage weight gain and FE as well as reduced muscle yield and HSI compared to fish fed the methionine-supplemented diets. Interestingly, taurine inclusion at 1% in the diet containing 0.49% methionine increased weight gain and feed efficiency of fish compared to those fed the diet without supplemental taurine or methionine. These results indicated that growth performance and body composition of hybrid striped bass did not respond to taurine supplementation when dietary methionine was adequate but did respond when dietary methionine was limiting.

An investigation on the effects of dietary protein level in juvenile Chinese mitten crab ( Eriocheir sinensis ) reared at three salinities: survival, growth performance, digestive enzyme activities, antioxidant capacity and body composition

A 50-day feeding experiment was conducted to investigate the effects of dietary protein level (26%, 34%, 43% and 52%) on the survival, growth performance, digestive enzyme activities, antioxidant capacity and body composition in the Chinese mitten crab (Eriocheir sinensis) reared at three salinities (0.5‰, 2‰ and 6‰). Survival rate (SR) showed a clearly decreasing tendency as the salinity elevated. The highest weight gain rate (WGR) was achieved in the treatment of 43% protein at the salinity of 0.5‰ and 2‰, and 26% protein at the salinity of 6‰ (p > 0.05). However, there was no significant interactive effect between dietary protein level and salinity on the SR and WGR of E. sinensis (p > 0.05). As salinity increased, the amylase activity and lipid deposition increased but the Na+/K+-ATPase activity decreased. The MDA content of E. sinensis was increased at the salinity of 2‰ than the other two salinities by low or moderate dietary protein (26–43% dry diet), but was significantly decreased by high protein (52% dry diet). Correspondingly, the activities of GSH-Px were increased at the relatively higher protein (43–52% dry diet). The significant interactive effect was only obtained between dietary protein level and salinity on the activities of CAT, GSH-Px and MDA content of E. sinensis. Dietary protein level had a more obvious positive effects on the EAA deposition at the salinity of 2‰ and 6‰, with the highest contents of essential amino acids (EAAs) achieved by 43% dietary protein. In conclusion, the relatively higher protein could benefit the E. sinensis by inhibiting the lipid peroxidation and increasing the deposition of EAAs at the salinity of 2‰. The elevated activities of amylase could account for the low protein (26%) requirement for E. sinensis reared at the salinity of 6‰.

EFFECTS OF EARLY WEANING OF PIGS TO A DRY OR LIQUID MILK DIET ON SUBSEQUENT GROWTH AND CARCASS MEASUREMENTS

Forty-five Yorkshire baby pigs from five litters (9 pigs from each litter and with mean body weight 1.9kg), at two days of age were randomly, within litter, left with the sow to 21 days of age (treatment 1), weaned to a 24% protein dry diet fed ad libitum (treatment 2), or to homogenized cow milk fed in restricted amounts four times daily to 21 days of age (treatment 3). From day 22, all pigs were fed a corn-soybean meal type diet containing 18% protein to 10 weeks of age, and a similar diet containing 16% protein from 10 weeks of age to slaughter at approximately 160 days. Average daily weight gain (ADG) and live body weight at slaughter were significantly lower, and feed/gain significantly higher among cow milk-fed pigs (treatment 3) than among pigs left with the sow until 3 weeks (treatment 1) and pigs weaned to dry diet (treatment 2). Backfat thickness, loin eye area, yield of lean cuts and dressing percent did not differ significantly among treatments. The results confirmed that weaning at two to three days to a dry diet fed ad libitum or to cow milk fed in restricted amounts four times daily is feasible, but overall performance from birth to slaughter of pigs weaned to a dry diet at two days of age was similar to that of pigs weaned at three weeks of age and superior to that of pigs weaned to cow milk at two days of age.

Effect of Feeding Wet Feed or Wet Feed Fermented by Bacillus licheniformis on Growth Performance, Histopathology and Growth and Lipid Metabolism Marker Genes in Broiler Chickens.

Simple SummaryHeat stress is an abiotic environmental factor that affects poultry performance and results in several physiological, immunological and behavioral changes in birds. Previous works have illustrated that wet feeding has been considered as a useful agent to improve birds’ ability to resist high ambient temperatures and to enhance our understanding of feed consumption limitations when broilers are fed dry diets. In broilers, wet feeding enhances nutrient use. This research reveals the impacts of three feeding methods (dry feed, wet feed or wet feed fermented with Bacillus licheniformis) on the growth efficiency, intestinal histomorphometry and gene expression of the lipid metabolism- and growth-related genes of broiler chickens. Our findings confirm improved growth and digestibility for fermented wet feed compared with control and wet feed diets; however, wet feed has a negative effect on performance compared with the control group (dry feed). Additionally, fermented wet feed caused a reduced hepatic gene expression of peroxisome proliferator-activated receptor γ (PPARγ) and increased that of fatty acid synthase (FAS).The present study evaluated the effect of three feeding methods (dry feed, wet feed or wet feed fermented with Bacillus licheniformis) on the growth performance, intestinal histomorphometry and gene expression of the lipid metabolism- and growth-related genes of broiler chickens. A total of 360 one-day-old Cobb-500 broiler chicks were randomly allotted into three groups containing four replicates with 30 birds each. The first group (control) was fed a dry mash basal diet. The second and third groups were fed wet feed and fermented wet feed. The final body weight and weight gain were reduced (p < 0.01) in the wet feed group, while they did not differ between the fermented wet feed and dry feed groups. Feed intake was not altered, and feeding on wet feed significantly (p < 0.01) increased the feed-to-gain ratio compared to the remaining groups. No differences between the three feeding methods in carcass characteristics, blood biochemistry and nutrient digestibility were observed except for crude protein digestibility, which was increased (p < 0.01) in the fermented wet feed group. Duodenal and ileal villi heights were elevated in birds fed fermented wet feeds, while crypt depth was not altered. The expression fold of IGF-1, GH and m-TOR genes in the pectoral muscle of birds fed wet feed was decreased (p < 0.05), while myostatin gene expression was elevated. Feeding on wet feed reduced the hepatic gene expression of PPARγ and increased that of FAS. In conclusion, wet feed negatively affected the broiler chickens’ efficiency under heat stress; however, fermenting the wet feed with Bacillus licheniformis improved feed utilization and birds’ performance compared to the dry feed group.

Development of a Group-Adapted Housing System for Pregnant Sows: A Field Study on Performance and Welfare Aspects

A Sow-Welfare-Optimized-Feeding (SWOF) system with group-adapted ad libitum liquid feeding was developed to ensure that both optimal nutritional and behavioral needs are met in group-housed pregnant sows. This system comprises functional areas and allows sows to have either a low- or high-energy diet according to their current weight in relation to their parity. This field study aimed to investigate how this new system influences sows’ body weight, health status (lameness), aggression parameters (integument injuries, vulva injuries, and displacements at the trough), feed intake rhythm, and litter performance. In parallel, these parameters were also recorded in the existing system (group-housed sows restrictively fed a dry diet). In the SWOF system, the probability of displacements at the trough and occurrence of vulva injuries were reduced, whereas sows could follow a natural biphasic feed intake rhythm. Though lameness scores and litter performance were not affected, lower body weights and more integument injuries were, however, observed. Yet, results can only partially be attributed to the feeding system per se due to confounding effects such as management practices and group size differences (larger dynamic group vs. stable group). Hence, the SWOF system seems promising with regard to animal welfare but remains to be further validated.

Clinical and Nutritional Follow-up of Cats with Chronic Kidney Disease Fed with a Renal Prescription Diet

Background: The use of prescription diets for cats with chronic kidney disease (CKD) is one of the main management approach of this disease in cats, and is considered a renoprotective strategy that may promote increased survival and/or improve quality of life, according to the stage of CKD. Besides that, nutritional assessment is important to monitor the maintenance of quality of life of the patients and their response to disease, especially those with chronic conditions. The aim of this study was to follow the clinical and nutritional status of cats with chronic kidney disease (CKD) IRIS stages II, III and IV fed with a renal prescription diet, followed for 12 months. Materials, Methods &amp; Results: Patients were fed exclusively with a dry renal prescription diet and medications for the management of CKD were prescribed when needed. Exclusion criteria were cats that already received a renal prescription diet or medications for the treatment of CKD. Cats were evaluated every 2 months, considering body weight (BW), body condition score (BCS), muscle mass score (MMS), clinical and laboratory parameters. In all assessments, a complete blood count and biochemistry were performed by conventional methods with the patient fasted for 12 h. In addition, urinalysis, urinary protein:creatinine ratio (UPC) and urine culture were performed from a urine sample collected by cystocentesis. The quantitative variables were tested for their stability on consecutive assessments using the non-parametric Friedman test, and did not present significant variation during follow-up, except for systolic blood pressure (SBP). Eight cats with a diagnosis of CKD were included in the study and 6 of them remained in the same CKD stage during follow-up. On cat died due to an unrelated CKD cause. Regarding nutritional assessment, 5 of 7 cats maintained BW during the 12 months. Of these, 4 also maintained MMS and BCS. Three of 7 cats presented a decrease in MMS, 2 of which presented also a decreased BW and one maintained BW.Discussion: IRIS staging results combined with Friedman’s analysis demonstrated that the diet and the clinical management were effective in the non-progression of CKD in this study. As renal injury is not expected to be reversed in CKD, the maintenance of cats in the same IRIS stages and the minimum variation of the parameters is considered a positive result in this study. Hypertensive cats started on antihypertensive therapy during the study, achieving adequate control of SBP in most cases, what can justify the variation of this clinical parameter over the 12 months. Hyperphosphatemia was a frequent alteration, included stage II cats, and presented a positive response to nutritional and medical therapy. Despite CKD staging progression was not observed in most cats using serum creatinine as a single parameter, some cats presented BW and MMS reduction, which may have influenced this result. Weight loss and muscle wasting may have occurred by several reasons, including periods of hyporexia, presence of concomitant diseases, aging process or reduced protein content on renal prescription diets. This study enhances the importance of the association of clinical and nutritional management in the maintenance of cats with CKD. We suggest that other studies are done during longer periods of time and with a larger sample to support the results found. We also suggest new studies to evaluate the protein requirements for cats with CKD.

Low doses of monensin for lambs fed diets containing high level of ground flint corn

Two experiments were proposed to evaluate the addition of monensin for lambs fed diets containing a high level of mature ground flint corn. The experimental diets were as follows: no inclusion of monensin (M0) and inclusion of 8 (M8), 16 (M16) and 24 mg kg–1 of monensin (M24). In experiment 1, eight cannulated wethers were divided into a double 4 × 4 Latin square experimental design to evaluate nutrient digestibility, plasma parameters and rumen fermentation. The experiment lasted 112 days, divided into four periods of 28 days each. In experiment 2, ninety-two lambs were used in a randomized block design to evaluate the performance over 56 days. In experiment 1, doses of monensin had no effect on nutrient intake (p ≥ 0.07) and digestibility (p ≥ 0.09). There was a quadratic effect for acetate molar proportion (p = 0.01), acetate to propionate ratio (p = 0.04) and rumen pH (p < 0.01). However, there was no effect on the molar proportion of propionate and butyrate. The monensin decreased linearly the total SCFA concentration (p < 0.01). The inclusion of monensin increased glucose (p < 0.01) and decreased lactate concentration in plasma (p = 0.05). In experiment 2, monensin decreased dry matter intake (p = 0.04). However, there was a quadratic effect for average daily gain (p = 0.03) and feed efficiency (p < 0.01), with the greatest values observed for the M8 diet. Thus, the inclusion of 8 mg kg–1 of dry matter diet (DM) improves ruminal fermentation and plasma parameters, resulting in greater growth performance in lambs.

Effects of feed energy and protein level on growth and pelt parameters in blue foxes (Vulpes lagopus) in the late growing-furring period

The aim of the present study was to determine whether a decrease in feed energy content would prevent extreme body weight (BW) gain and fatness in blue foxes in the late growing-furring period, without compromising pelt quality or pelt size. BW gain, body mass index (BMI), body condition score (BCS), and pelt characteristics were studied in 60 blue foxes divided into four equal-sized groups from mid-October until pelting (50 days). Experimental diets in were “high energy – high protein”, “high energy – low protein”, “low energy – high protein”, and “low energy – low protein”. High-energy diets contained 19.3 MJ metabolisable energy (ME) in kg dry matter (DM) and high-protein diets contained digestible crude protein (DCP) 20% of ME. Low-energy diets contained 16.3 MJ ME in kg DM and low-protein diets DCP 17% of ME. Feeding was gradually increased towards ad libitum. Reduced ME intake had no effect on pelt size or pelt quality. High-energy feeds resulted in heavier animals with higher BMI. However, the final BW exceeded 20 kg and BCS was “fat” or “extremely fat” in all groups.

A cross-sectional study of pet owners' attitudes and intentions towards nutritional guidance received from veterinarians.

Beliefs of pet owners strongly influence their decision-making surrounding their pets' diet. Thus, nutritional guidance is an essential component of veterinary practice and integral to managing rising rates of pet obesity. This study examined pet owners' trust of, perceived effectiveness of, and intentions to follow nutritional guidance received from their veterinarian in managing their pets' diet. A cross-sectional study of 1402 dog and cat owners in the USA and Canada was conducted using an online questionnaire tool. Data were analysed using descriptive statistics and logistic regression modelling. Clients are concerned about the effectiveness of veterinary nutrition recommendations. Cat owners were more likely than dog owners to consider the nutritional guidance they receive from veterinarians effective for their pets' diet (1.75, P=0.04). Length of pet ownership, feeding dry diets and frequency of veterinary visits were all positively associated with owners considering veterinary nutritional guidance to be effective in managing pets' diet. Identifying these perspectives can aid in developing strategies to provide nutrition support to pet owners to improve their perceptions of, self-efficacy with, and compliance with veterinary nutrition recommendations.

PSX-35 Late-Breaking Abstract: Use of total tract NDF and starch digestibility in beef cow and replacement heifer diet formulation

Abstract The objective of this trial was to evaluate the effectiveness of using the total tract neutral detergent fiber (TTNDFd) and starch digestibility methodology in the formulation of beef cow and replacement heifer rations. This methodology ultimately applies to the estimation of energy availability to the animal and accompanied performance as outlined by the NASEM 2016 Nutrient Requirements of Beef Cattle publication. Multiparous, Angus cows during the last two months of gestation and yearling replacement, Shorthorn heifers comprised the study. Cows received one of four, dry ingredient diets while heifers received a corn silage-based diet. Feed nutrient evaluation along with intake were documented and applied to the NASEM model for these cattle. Results were compared to actual performance. Acid detergent fiber (ADF) derived energy estimates which generally accompany commercial laboratory feed analysis reports were compared as well. A T-test between actual and projected growth was used to describe the difference. The T-test between the TTNDFd/Starch derived results did not show any statistical difference between the actual and projected results for heifers P(T&amp;lt; =t) 0.15 with an average ADG bias of -0.06 Kg. The cow results over the four diets P(T&amp;lt; =t) ranged from 0.41 to 0.004 with an average bias of 0.04 to 0.27 Kg overestimating ADG. The T-test between the ADF derived results showed a difference between the actual and estimated values for heifers P(T&amp;lt; =t) 0.0004 with an average ADG bias of 0.2 Kg. The cow results over the four diets likewise over estimated available energy substantially. Here the test ranged from P(T&amp;lt; =t) 0.03 to 0.0001 with an average bias of 0.35 to 0.7 Kg. It appears that TTNDFd methodology should be strongly considered in the evaluation of forages and in the development of ration formulation software for beef offered high levels of fiber in their ration.

185 Effect of zinc source and implant strategy on performance, carcass characteristics, and tissue mineral concentrations in finishing beef steers

Abstract A 126-d study utilized 72 Angus-cross steers (411 ± 16 kg) in a 3 × 2 factorial to examine the effects of Zn source and implant strategy on performance, carcass characteristics, and tissue Zn concentrations. All steers received 70 mg Zn/kg dry matter (DM) from ZnSO4 + 30 mg Zn/kg DM from one of three sources: zinc hydroxychloride (ZnHC), zinc glycinate (ZnG), or zinc sulfate (ZnS). Implant (IMP) strategies included: no implant (NoIMP) or Component TE-IS and Component TE-200 (IS/200) on d 0 and 57, respectively. Steers were blocked by weight into pens of 6 and fed a dry rolled corn-based diet via GrowSafe bunks. Data were analyzed using ProcMixed of SAS, with fixed effects of Zn, IMP, and the interaction. Liver and muscle collected on d -5, 14, 71, and 120 were analyzed for Zn concentration and data were analyzed as repeated measures (repeated effect = day). Steer was the experimental unit (n = 12/treatment). Final body weight and overall average daily gain tended to be decreased for ZnHC compared to ZnS, with ZnG intermediate within IS/200 (Zn × IMP; P ≤ 0.07). No interaction was observed for overall G:F or DM intake (P ≥ 0.41), but both were greater for implanted steers (P ≤ 0.01), while overall G:F was improved for ZnS compared to ZnHC and ZnG (P = 0.02). Carcass characteristics were unaffected by Zn × IMP or Zn source (P ≥ 0.12), but IS/200 improved HCW, DP, and REA (P ≤ 0.01). Implant increased liver Zn (P = 0.02) concentrations. Within IS/200 ZnG tended to have greater muscle Zn than ZnS while ZnHC was intermediate (Zn × IMP; P = 0.09), potentially indicating differences in availability of Zn source to growing muscle. These data suggest Zn source and implant influence performance and tissue Zn concentrations.

Effects of dietary n‐3 LC‐PUFA on the growth performance, gonad development, fatty acid profile, transcription of related genes and intestinal microflora in adult sea urchin ( Strongylocentrotus intermedius )

A study was conducted to investigate the effects of dietary n-3 LC-PUFA on the growth performance, fatty acid profile, transcription of related genes and intestinal microflora in adult sea urchin (Strongylocentrotus intermedius). Kelp (Laminaria japonica) and four formulated feeds with graded levels of n-3 LC-PUFA (0%, 0.5%, 0.8% and 1.0% dry diet) were prepared as the experimental diets. Each diet was randomly allocated to ten adult sea urchin individuals. The feeding period lasted for 90 days. Results showed that gonadosomatic index (GSI) of adult S. intermedius fed formulated feeds was significantly higher than that fed kelp (p < 0.05), while weight gain rate (WGR) showed no significance between kelp and feed groups (p > 0.05). Neither WGR nor GSI showed significant differences among the four feed treatments (p > 0.05). Notably, ARA and EPA in the gonads of S. intermedius fed the feeds devoid of n-3 LC-PUFA were comparable to that fed the feeds with 0.5% n-3 LC-PUFA (p > 0.05). Transcription of Elovl4 and Δ5-desaturase in the intestine and gonad significantly decreased as dietary n-3 LC-PUFA increased (p < 0.05). Proteobacteria and Bacteroidetes (phylum level) and Psychromonas and Sulfurimonas (genus level) were the most abundant bacteria species in the intestine of S. intermedius. The abundance of Sulfurimonas was comparable in the S. intermedius fed kelp and the feed with 0% n-3 LC-PUFA, which was significantly higher than that fed the other formulated feeds (p < 0.05). These results indicated that S. intermedius seems to have a low requirement for n-3 LC-PUFA to sustain its normal growth and gonad development. The increased transcription of rate-limiting enzymes (Elovl4 and Δ5-desaturase) could be responsible for the considerable amounts of EPA and ARA in the gonads of S. intermedius when fed feeds without LC-PUFA. The intestinal microflora were affected to a certain extent by the die categories and the n-3 LC-PUFA in the formulated feeds. It is speculated that some unknown bacteria in the genus of Sulfurimonas could participate in the synthesis of LC-PUFA.

Dietary supplementation with Lactobacillus plantarum and β-glucan affects immune parameters in the tench (Tinca tinca) fry.

The aim of the experiment was to examine the effect of a diet enriched with Lactobacillus plantarum and/or β-glucan on the immune parameters in the juvenile tench (Tinca tinca). Fish were fed for 14 days different diets (phase 1 of the experiment), a dry commercial starter feed in the control group or the same feed supplemented with: 1% β-1,3/1,6-glucan in group G, 108 cfu L. plantarum g-1 in group L, 1% β-1,3/1,6-glucan + 108 cfu L. plantarum g-1 in group G+L. During consecutive 14 days all fish were fed the commercial feed alone (phase 2). The stimulating effects of the tested preparations was evaluated twice, at the end of each experimental phase. Dietary supplementation of β-1,3/1,6-glucan considerably improved the humoral innate immune response (activity of lysozyme and total Ig) and the pinocytotic activity of phagocytes. Supplement of L. plantarum improved the ability of the head kidney phagocytes (RBA) to carry out oxygen burst in L and G+L groups. A similar effect was observed for the killing activity of phagocytes (PKA) from the head kidney after the stimulation of A. hydrophila, and the effect persisted for two weeks after the commercial feed regime was resumed. A significant increase in the proliferative activity of B lymphocytes originating from the head kidney was observed in groups L and G+L. The study has revealed that the addition of the tested G+L synbiotic to dry diet stimulates the innate immune response mechanisms in the juvenile tench.

Supplementation of Yeast Cell Wall Fraction Tends to Improve Intestinal Health in Adult Dogs Undergoing an Abrupt Diet Transition.

When owners decide to change their pet's food, a rapid transition may cause gastrointestinal distress. Yeast products may help with digestive upset during diet transition due to the bioactive compounds they possess, which may lead to improved intestinal morphology and integrity, modified gut microbiota, and modulated immune responses. The objective of this study was to determine the effects of a yeast cell wall fraction supplement on measures of gut integrity and fecal characteristics of adult dogs undergoing an abrupt diet transition. Twelve adult female beagles (mean age: 5.16 ± 0.87 years; mean body weight: 13.37 ± 0.68 kg) were used in a replicated 4 × 4 Latin square design with four 28-day experimental periods. During days 1–14, dogs were fed a dry kibble diet and supplemented with a placebo (cellulose; 125 mg/d) or yeast product (365 mg/d; equivalent to 0.2% of diet). During days 15–28, dogs remained on their placebo or yeast treatments but were rapidly transitioned to a canned diet or high-fiber diet. Fresh fecal samples were collected on days 13, 16, 20, 24, and 27 for measurement of pH, dry matter, calprotectin, immunoglobulin A (IgA), Escherichia coli, and Clostridium perfringens. Blood samples were collected on days 14, 17, and 28 to measure serum lipopolysaccharide-binding protein concentrations. All data were analyzed using the Mixed Models procedure of SAS 9.4. Fecal pH, dry matter, calprotectin, IgA, and E. coli were not affected (P > 0.05) by treatment before diet transition. Dogs supplemented with yeast cell wall fraction tended to have higher (P = 0.06) fecal C. perfringens counts than the controls. After diet transition, most parameters were not altered (P > 0.05) by treatment except that yeast-supplemented dogs tended to have higher (P = 0.06) fecal IgA than controls. Our results suggest that the yeast product may modestly improve intestinal health after an abrupt diet transition in adult dogs by enhancing intestinal immunity.

Effects of dietary arginine levels on growth, intestinal peptide and amino acid transporters, and gene expressions of the TOR signaling pathway in tiger puffer, Takifugu rubripes

This study aimed to determine the dietary arginine requirement of tiger puffer (Takifugu rubripes), and to assess the effect of dietary arginine levels on intestinal peptide and amino acid transporters, and target of rapamycin (TOR) signaling pathway in muscle. Six experimental diets were formulated to contain 480 g kg−1 crude protein from fishmeal, corn protein concentrate and crystalline amino acid premix with graded levels of arginine (19.1, 21.5, 24.4, 26.7, 30.0 and 32.5 g kg−1 of dry diet). Each diet was randomly fed to triplicate groups of 25 fish (an average initial body weight of 19.97 g) per tank. Final body weight, specific growth rate (SGR), feed efficiency ratio, protein efficiency ratio and protein productive value increased with the increase of dietary arginine levels from 19.1 to 24.4 g kg−1 (p < 0.05), and then showed a declining trend although there was no significant difference. With the increase of dietary arginine levels, intestinal oligopeptide transporter 1 (PepT1), cationic amino acid transporter 1 (CAT1) and y+ L-type amino acid transporter 2 (y+LAT2) mRNA levels increased at first and thereafter showed a decreasing trend, where a break point was observed in the 24.4 g kg−1 arginine group. The expression of b0,+-type amino acid transporter (b0,+AT) in intestine was significantly higher in the 21.5 and 24.4 g kg−1 arginine groups compared with the 32.5 g kg−1 arginine group (p < 0.05). Gene expressions of TOR, ribosomal protein S6 kinase 1 and eukaryotic translation initiation factor 4E-binding protein 1 in muscle were not statistically different in all treatment groups (p > 0.05). In conclusion, an optimal level of dietary arginine stimulated intestinal peptide and amino acid transporters, while gene expressions of TOR signaling pathway in muscle were not responsive to dietary arginine levels. Based on nonlinear regression analysis of SGR, the dietary arginine requirement of tiger puffer was estimated to be 24.40 g kg−1 of dry diet (50.12 g kg−1 of dietary protein).

Effects of dietary protein and cellulose levels on growth performance, antioxidant status, immune response and inflammation in juvenile yellow catfish ( Pelteobagrus fulvidraco )

In this study, nine experimental diets were formulated to contain three graded levels of protein (40, 45 and 50% of dry diet) and three graded levels of cellulose (0, 5 and 10% of dry diet). These diets were then fed in triplicate to yellow catfish for 90 days. We found that fish fed diets containing 45% and 50% protein had more weight gain than did fish fed a 40% protein diet, while fish fed diets supplemented with 5% cellulose achieved the greatest weight gain and the lower feed conversion ratio. We found that as dietary cellulose and protein levels were increased, the activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase), immune response parameters (alkaline phosphatase, acid phosphatase, phagocytic index, respiratory burst, complement 3 and 4) and the mRNA level expression of copper/zinc superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase all rose. In contrast, rising cellulose levels were associated with decreased malondialdehyde contents and increasing tumour necrosis factor, interleukin 1 and interleukin 8 mRNA expression. Overall, our results indicate that dietary protein supplementation can enhance yellow catfish immune functionality and that while dietary protein impacts on the immune response are influenced by dietary cellulose levels, increased dietary cellulose was associated with inflammatory gene upregulation.

Dietary Allicin Improved the Survival and Growth of Large Yellow Croaker (Larimichthys crocea) Larvae via Promoting Intestinal Development, Alleviating Inflammation and Enhancing Appetite.

A 30-day feeding experiment was conducted to investigate effects of dietary allicin on survival, growth, antioxidant capacity, innate immunity and expression of inflammatory and appetite related genes in large yellow croaker larvae. Four iso-nitrogenous (53% crude protein) and iso-lipidic (19% crude lipid) diets were formulated via supplementing graded levels of allicin (0.0 (the control), 0.005, 0.01, and 0.02% dry diet, respectively). Results showed that, among dietary treatments, larvae fed the diet with 0.005% allicin had the highest survival rate (SR) (P < 0.05), while larvae fed the diet with 0.01% allicin had the highest specific growth rate (SGR) (P < 0.05). Activities of α-amylase in both pancreatic (PS) and intestine segments (IS) of larvae fed the diet with 0.01% allicin were significantly lower than that in the control (P < 0.05). On the other hand, the supplementation of 0.01% allicin in diets significantly increased activities of alkaline phosphatase (AKP) and leucine aminopeptidase (LAP) in the intestinal brush border membrane (BBM) of larvae than the control (P < 0.05), indicating the promoting roles of allicin on fish larval intestinal development. Moreover, compared to the control, both the nitric oxide (NO) content and the activity of nitric oxide synthase (NOS) were significantly up-regulated in larvae fed the diet with 0.005% allicin, and catalase (CAT) were significantly upregulated in larvae fed the diet with 0.02% allicin (P < 0.05). Transcriptional levels of pro-inflammatory genes including cyclooxygenase-2 (cox-2), interleukin-1β (il-1β) and interleukin-6 (il-6) significantly decreased with increasing allicin, compared to the control. The expression of appetite genes including npy, ghrelin and leptin significantly increased with the prolonged fasting period, and dietary allicin supplementation significantly increased the transcriptional level of neuropeptide Y (npy) at 0.01%, while increased the transcriptional level of leptin in larvae at 0.02% dosages (P < 0.05). These results showed that the supplementation of 0.005% – 0.01% allicin in diets could improve the survival and growth of large yellow croaker larvae probably by promoting intestinal development, alleviating inflammation and enhancing appetite.