The Effects of Food Intake and Its Fat Composition on Intestinal Echogenicity in Healthy Dogs

Abstract

Dogs presenting for ultrasonography due to suspected gastrointestinal disease might have residual ingesta and this could have an affect on the appearance of intestinal mucosa unrelated to pathology. The purpose of this prospective descriptive study was to determine effects of a recent meal consisting of the recommended daily fat content (meal 1) and a higher fat one (meal 2) on mucosal echogenicity in healthy dogs. Sixty client-owned and clinically healthy dogs were recruited. Two meals, one with 15% fat dry matter basis (meal 1) and a second with 1.5 ml/kg body weight corn oil added to result in a range of 41-63% fat dry matter basis (meal 2), were fed 1 week apart after a 12 h fast. Mucosal echogenicity scores were assigned at fasting, immediate postprandial and at 60 min after each meal. Duodenal scores were significantly greater for meal 1 at 60 min (P < 0.001) as opposed to fasting and immediate postprandial. With meal 2, the duodenal score was significantly different (P < 0.001) at the immediate and 60-min data point compared to meal 1. Jejunal scores were significantly greater for meal 1 at the 60-min data point (P < 0.001) as opposed to fasting and immediate postprandial. With meal 2, the jejunal score was significantly different (P < 0.001) only at the 60-min data point compared to meal 1. Intestinal mucosal echogenicity can be increased in healthy dogs after food intake, regardless of fat content. This effect should be taken into consideration when increased mucosal echogenicity is identified in clinical patients.

Ex Vivo Correlation of Ultrasonographic Small Intestinal Wall Layering With Histology in Dogs

“…This assumption is further supported by two recent studies, which demonstrated that oral administration of corn oil or a high‐fat diet could induce/increase similar hyperechoic mucosal changes ultrasonographically in healthy dogs and dogs diagnosed with lymphangiectasia. These transient ultrasonographic mucosal changes were suspected to reflect physiological postprandial lacteal dilation, and in one of these studies, the changes observed in healthy dogs overlapped the ultrasonographic findings described in dogs with lymphangiectasia and enteritis . This ultrasonographic finding should therefore be interpreted with caution, in relation with the clinical history and blood work of the patient, as well as delay between ultrasonographic examination and last meal.…”

“…Due to the lack of extensive history and blood work in the dogs included in this study, we cannot definitively conclude that these ultrasonographic findings were clinically nonsignificant. However, due to the minor histological changes associated with them, their high prevalence, the recent literature describing them as incidental findings, and the fact that most of these findings are commonly observed in a clinical setting at our hospital, in healthy dogs as well, it should also be considered that they could merely be associated with improved ultrasonographic transducer technology.…”

“…These ultrasonographic features could be of importance as noninvasive markers of underlying intestinal disease, but studies correlating their presence to histology are lacking. Recently, similar transient ultrasonographic changes, overlapping with the ultrasonographic findings seen in dogs with lymphangiectasia and enteritis, have been described in the mucosa of healthy dogs following ingestion of a high‐fat diet . The intestinal layers described in literature ultrasonographically are only assumed to correlate with the histological layers (mucosa, submucosa, muscularis propria , and serosa), based on publications in people using antiquated ultrasound technology, but direct correlation of these ultrasonographic layers with histology has not been confirmed in dogs using high‐resolution ultrasound equipment.…”

How useful is abdominal ultrasonography in dogs with diarrhoea?

“… suggested that increased mucosal echogenicity may be a more accurate indicator of IBD than intestinal wall thickness in dogs with chronic diarrhoea; however, a more recent study found that up to 50% of normal dogs had hyperechoic foci in the intestinal mucosa if scanned within 1 hour of a meal (Gaschen et al . 2016). Hence, the value of using this finding to help select further diagnostic tests is doubtful because it may not represent a pathological change.…”

“…Hence, upper and lower gastrointestinal endoscopy may be employed regardless of ultrasound findings. Gaschen et al (2008) suggested that increased mucosal echogenicity may be a more accurate indicator of IBD than intestinal wall thickness in dogs with chronic diarrhoea; however, a more recent study found that up to 50% of normal dogs had hyperechoic foci in the intestinal mucosa if scanned within 1 hour of a meal ( Gaschen et al . 2016 ).…”